I actually like zyra's passive as is

Yes,even the delay.

I don't care that if I'm doing very well I make no use of it,because I'm already doing very well,I don't need it.

It's good at making people dance between plants or being set up with a snare first if you know that you are going to die,or just confuse people as to when you'll use it in a teamfight,as you can stay that way for quite a while and also it still applies aura items(like banner/aegis).

I'm more bothered with the fact that for a champion focused on disengage she's very ineffective against high mobility divers,or how riot completely wussed out on her upcoming buffs,probably meaning two more years of nothing.