Zyra Hasn't been Touched Much this Season, (heh, Season) What's up with that?
What is really cool about Zyra, I believe, is her plants. They're the most interesting and unique "Pet" in the game, in my opinion, able to be put on steroids, morphed, and changed, depending on what spells Zyra hits them with.
With all that being said, I think Zyra's base stats (besides maybe her Hp) are in a Great spot. Her scalings and mana costs are pretty normal for a Mage or Poke Support for her power level. To fill the hole that prevents her from being played over other champions, I believe her Plants need to be Reworked. Zyra is the Lady of Plants, like come on, this can be COOL!
What if, instead of only a measly two plants, Zyra had the ability to spawn as many as 3 at a time, and double the growth with her ult? I think that'd be really cool.
My suggestion to give Zyra her power as a Support (Sorry, nothing for Mage point of view, but I suppose she is still playable Mid):
-Change her passive to "Rise of the Thorns": When Zyra's spells hit champions, a Plant spawns near them. Depending on which spell is used, the plant has varying effects (can only occur 1/2/3 times per spell at level 1/6/11): These plants will prioritize enemy champions, or who Zyra is attacking. They passively attack once per second. Q, Deadly Bloom- The Plant has increased Range and Damage. W, Photosynthesis- The Plant Reduces Champion Healing and Damage for a few seconds. Upon attacking an enemy champion, Zyra's Cooldowns are reduced by .5 with each attack. E, Grasping Roots- The Plant Reduces Champion Movement Speed for a few seconds. R, Stranglethorns- All of the spawned plants gain Additional Attack Speed, and Grant Vision of their Targets.
-Rework W to "Photosynthesis": Zyra channels for 1.5/1/.5 seconds before healing herself (and another ally champion) through Photosynthesis. Zyra will spawn a plant nearby the Champion she selects to heal, although she can heal just herself for a greater heal.
The above change would remove Zyra's W, Rampant Growth, but the CDR provided is compensated for in the W plant effects description, and makes her feel more healthy and rewarding.
That is pretty much it, my goal was to shift Zyra's power into her spells, and more into her plants. I hope you like it, if not, let me know why!
Hopeful for Changes this Preseason!
Thanks~ :D