Ah, you mean that in Southern Swamp the plants are a surprise pain in the backside if you prep TT on, say, a Vicious Token run, relatively to Ick Swmp where they were ment to be a pain in the backside regardless? If that's the case, I agree ^^
Oh well, it was a bit of a "bites you in the donkey" wtf moment - most other altar preps mean what they mean (all of them), and don't have a "also you're royally screwed in condition X" clause that would make you paranoid about prepping them. I guess it'll work out.
It does, however, make Ick Swamp potentialy super-easy if you prep TT with anything in any circumstances, though. Seeing that Binlor sort of does this for heavy mazes, I guess I don't know what to think.