What I want is:
-A small story (like what jonasas2 said: e.g raididing, escape to safety, cure to zombification).
-Much more minigames (50 instead of 20?)
-More types of puzzle plus a few of the old ones (say 20 Vase and I,Zombie combined) plus 40 more others.
-Endless of all survival types. Maybe a extra hard "Insanity" mode or a conveyor belt, no mower survival.
-More Adventure levels, depending on story length. Maybe 80?
-Cheat Codes, Zen Garden( Hydroponic Garden/Cave Garden?), the works.
-Car Shop selling Solar Powered Gadgets? Maybe 2 Gadget Slots? And of course, Upgrades and Zen Garden tools. We could throw in one special thing, like the Imitater in the original. Something to reduce sun cost for a plant, or make it recharge 1.5x faster?)
-And the Zonbatar creation thing. I did want a Level Creater, but that's too difficult to code and there are countless ways to give minigames and levels a motive.