I think Zyra's W should either: Do Damage when the enemy steps on it
OR
Reveal the enemy for 8 seconds (up from 2 seconds) and lower their magic resist by 10%
Similar to Caitlyn and Nidalee's traps, it will reveal for longer and lower the resist.
I prefer the 2nd option btw
shes already got enough burst its like asking to give 
more passive Q AP
Her W doesn't need a buff at all. The buds stay there for forever and when she has the ability she gets CD. When she activates a bud the burst is real. Trust me she doesn't need a buff. Plant is already OP support or mid.
Zyra's W isn't a trap really, and should be a dormant and defenseless plant at that point, so i'm not for the idea of it doing damage personally.
I'm not sure what logic they used for it to reveal the enemy, but I would say I like #2 better as well.
Just a kind of random thought, You'd think that a plant and even with her taunt about having friends all around, You'd think she could communicate with plants and could have some kind of cool ability that revealed all enemies on the map (Like Twisted Fate's Ult) I don't really know how to suggest something like that in her kit Cause it'd obviously be pretty good.
Maybe something with her W that would have a second Area that if a player stepped in the area (even if in the fog of war) that she could be alerted to their presence.
More back to the original thought though. What if her W gave sight of enemies that stepped on it, and it lasted longer, but only she could see it (as a trade-off) Kind of on the idea that the plant is feeding her information, not neccessarily your whole team.
I don't believe there's anything like this in the game, and it's kinda iffy in a way, I just kind of get into the themes and like to work them in different ways.
I guess a good question for you is, why do you think she needs a buff?
Zyra is already broken, really no need for any sort of buffs.
