So, I really like PvZ2. I'd just like to sum up all the plants (the only one I don't have is Jalapeno) in specific rankings. I'll try to be as unbiased as possible. This will take awhile.
S- Excellent. A S rank plant is especially useful in many varied situations, and are easy to use.
A- Great. An A rank plant is a good plant that does it's job exceptionally well, and has only a few minor flaws.
B- Good. A B rank plant is fine and simple. They might not be amazing in Endless Zones, but they get their job done on normal levels.
C- Average. A C rank plant is more or less only usable in a handful of situations. But they lack in terms of power or effectiveness.
D- Below Average. A D rank plant is something that's pretty mediocre, and is only usable in specific situations.
F- BotB (Bottom of the Barrel). A F rank plant is something that's really unreliable, and are only usable in early levels or incredibly specific situations. Near useless otherwise.
Peashooter- D rank. While this is a low rank, it's not the plant's fault for being eh. It's the very first plant, and without it, you wouldn't be alive now would you? Despite this, Peashooter lacks a lot in later levels, and is outclassed by virtually every other offensive plant there is.
Sunflower- C rank. Again, with your Sunflower, we wouldn't be here. Sunflower is in the S rank in early levels (particualy AE), but of course fall into the C rank when compared to the likes of the Twin Sunflower and Sun-shroom.
Wall-nut- B rank. A decent basic wall that does its job well. While others outclass it, it's not bad in the slightest.
Potato Mine- B rank. Not much to say, it clear small clumps nicely, and is great until of course outclassed.
Cabbage-pult- D rank. It's just a Peashooter, next.
Bloomerang- F rank. Okay, here he is, the infamous, useless Bloomerang. He's technically better than already mentioned offensive plants, but let's be honest, he's pretty bare bones, and Peashooter/Cabbage-pult are cheaper anyway. He's supposed to be a counter to the Camel Zombies, mkay, makes sense. But why is it outclassed by every AoE plant in the game? It needs something to distinguish it from the others, just because it's the first one, doesn't means it has to be total crap. The only fun thing with him is using it against Jester Zombie.
Iceberg Lettuce- B rank. Pretty nice, it may not do too much, but Lettucy gets a simple job done, not really outclassed by anything either, just has sidegrades with different purposes.
Grave Buster- A rank. How to make him better than he was in PvZ1? Make him 0 sun, a tad slower recharge, and make graves a bigger threat. A great world exclusive plant that doesn't have much to talk about.
Bonk Choy- C rank. Mmm, eh. Egypt plants are pretty boring, but it does the job of being the first close range plant, and has something to make it different (nice plant food, ability to hit behind.)
Repeater- B rank. Ahh, classics never fail don't they? (excuse Chomper) Really versatile, and Red Stinger is a bit better than him, but Repeaty has Torchwood on his side.
Twin Sunflower- A rank, While Sun-shroom is considered the master sun producer (to me), she's for more expensive things to be put out faster, rather than just filling the screen with cheap Sun-shrooms.
Kernel-pult- B rank. Way better than Cabbage-pult by a long shot, the butter comes in not too often to be overpowered, but just enough to be efficent.
Snapdragon- S rank. EEEEYUP! Gotta love this guy. Great range, attacks fast, nice amount of damage, pretty much the whole enchilada, oh wait, wrong guy.
Spikeweed- C rank. Sure you need two to kill a regular zombie, but eh, he's okay. Wish he would pop Glitter Zombie's rollerstakes though...
Coconut Cannon- A rank. Most expensive plant so far, but eh. He does a great job being a a cheaper Cob Cannon (Banana Launcher tho). And has a nice plant food.
Threepeater- C rank. Not much, cheaper sun cost is nice, but it doesn't do anything eye poppin'.
Spikerock- A rank. Gargantuar stall FTW.
Cherry Bomb- A rank. Gargantuars go down to half health, I liek that!
Chili Bean- C rank. My least used early set-up plant, Potato Mine and Stunion do it better.
Pea Pod- B rank. Why spend 625 sun for a better Gatling Pea when you can spend 500 for a Gatling Pea? Versatility is a cool thing.
Lightning Reed- C rank. Not diggin' the Westies so far, he's good against chickens and weasels, but not much else.
Tall-nut- B rank. Okay, that's better. A stronger Wall-nut, though there are a lot of zombies that don't eat.
Melon-pult- A rank. Splash and heavy damage for dayz.
Winter Melon- S rank. Do I need to explain? Fast recharge, heavy damage, cooling, splash cooling might I add, and is probably the most overused plant in Endless Zones.
Laser Bean- B rank. R.I.P Bloomerang, may you never be used again.
Blover- A rank. See ya later jetpacks! And seagulls, and imps, and parrots, a lot of things.
Citron- C rank. Charges a tad slow, but works well with Laser Bean.
EM Peach- A rank. Stalling OP robots is fun.
Infi-nut- A rank. That plant food tho.
Magnifyng Grass- S rank. Okay, okay, here me out. Grassy is in my opinion, one of the best plants along with Winter Melon and Snapdragon. With careful timing and a ton of Sun-shrooms, Sun Beans, or Toadstools, you can combine her with a strong plant like Winter Melon to deal with big threats in a quick second, lookin' at you BWB zombies...
Tile Turnip- B rank. Never really tried using it, but I've seen it's crazy power, eats sun like Grassy though.
Sun-shroom- S rank. OP, gotta love him.
Puff-shroom- B rank. Imitater him up and grab a Power Lily and have some fun.
Fume-shroom- B rank. Another Bloomerang R.I.P.E (there's a plant pun in there), great plant food.
Sun Bean- A rank. Conehead + Grassy = Sun.
Magnet-shroom- C rank. Nice against Punks, but needs more to steal to be better.
Big Wave Beach
Lily Pad- B rank. Just your Lily Pad...what am I supposed to say?
Tangle Kelp- B rank. Killer plant food and is good with Octos and Fishermen, hate that tides wipe him out though.
Bowling Bulb- D rank. UGHHH.....so, BB (not that guy). So much potential, why can't your stronger bulbs come more often? You'd be perfect...
Guacodile- A rank. Great to work with stalling plants. I think I like him more than I should.
Banana Launcher- B rank. I was too harsh on him, he's great when paired with the right plants. Though he shouldn't be used by himself.
Hot Potato- S rank. She's a Grave Buster which has more uses (Hunter, winds, Troglobite)
Pepper-pult- B rank. Sluggish recharge is the only thing I don't like. So, IMITATE 'EM.
Chard Guard- S rank. Best defensive plant for me, Infy is second.
Stunion- A rank. Better than Icebergy in some cases.
Rotobaga- B rank. Helps a lot in BWB, easier pattern than Starfruit to work with.
Lookin' like the best ranks so far!
Red Stinger- A rank. Better Repeater, other forms are okay-ish, though the main form is where he shines.
A.K.E.E.- B rank. Works amazingly with Reddy, dream team FTW.
Endurian- C rank. Wish he had more health, but he's fine.
Stallia- B rank. Another great stalling plant, or stallia plant, whatever.
Gold Leaf- D rank. Why are you world exclusive...
Neon Mixtape Tour
Phat Beet- B rank. Not as good as Snapdragon, but has its uses.
Celery Stalker- B rank. Wish he wasn't glitched in some worlds, great set-up plant otherwise.
Thyme Warp- C rank. Again with the world exclusives, and healing.
Garlic- B rank. Okay I guess, hate how he was nerfed. Though Imitater makes him amazing.
Spore-shroom- S rank. Plant one get as many as it kills free.
Intensive Carrot- S rank. He can revive Hypno-shrooms, boosted one, let that sink in.
This'll be a long one, get ready for a doodly doo.
Snow Pea- C rank. Better than Peashooter...I guess.
Power Lily- S rank. Endless Zone life saver.
Squash- B rank. He's Squash, attacking behind is helpful.
Torchwood- B rank. Pea Pod + This + Plant Food = 15nds per attack.
Jalapeno- Don't have :I
Imitater- S rank. Great with E Berry and Power Lily.
Starfruit- B rank. Okay, never used it too much.
Hypno-shroom- B rank. Gargs are your side is sweet revenge.
Pea-nut- C rank. Peashooter Wall-nut, next.
Chomper- F rank. UUUGHHH, WHY?!
Homing Thistle- A rank. Underused, do miss Cattail though.
Hurrikale- A rank. Go back to dat way.
Fire Peashooter- A rank. Fixes Pepper-pult's issues.
Lava Guava- A rank. Lotta A's, lava is especially helpful with excavators.
Toadstool- B rank. Thank you for being a better Chomper.
Cactus- B rank. Got a nice change.
Electric Blueberry- B rank. Fine, except for one thing, WHY DO YOU TARGET BASIC ZOMBIES WHEN THERE IS A PUNK ABOUT TO KILL YOU!?
Holiday Plants, Jingle Jangle
Ghost Pepper- S rank. You know why.
Sweet Potato- B rank. Not bad.
Sap-fling- C rank. Only useful with Pepper-pult and MC's.
Dandelion- C rank. Never really used.
Strawburst- B rank. Pretty nice, great with the Carrot.