Would you rather Vazkii taken the other approach? Removed all the generating flora EXCEPT for the passives? As it seems every other person I come across talking about botania seems to want endless passives back. As it stood, it's a case of effort vs conveinece. Passives, without withering, are far in away much simpler to set up, to the point where people used solely hydrogea towers for their mana, with no intention of at least trying non-passive flowers, as hey, I've got 1000 hydros and have more mana than I could ever need, I don't need other flowers. (Yes I am possibly exaggerting here) I'm sure that would have caused even more uproar.
DeathofTime makes alot of good points. This also reminds me slightly of AE2's introduction of channels and the vocal backlash against them, simply due to them being more effort, and requiring thought. (Personally I prefer channnels, although there are parts of AE2 I'm not so fond of.) With Passives, Particually hydrogeanas, being the end-all-be-all of mana, the biggest thought you had with botania is automating mana infusions, the functonal flowers, such as the clayconia and pure daisy, which are often nowhere near as complex to automate (especially without restricting yourself to Vanilla + Botania), the Terrestrial Allogamtion plate and runic alter, which are fair challenges, and two I'm probibly going to take on sooner or later.