When we actually get to see what features BF3 will have, we will make the decision then, but I wouldnt put it out of the possibility.
If its 100+ players, with huge maps and those new fancy sound engine and physics engine, I think it would be hard to get us NOT to get some kind of minimod started on it
However, if all other games are any indication, a BF3 might just be a consolified game with 24 max players, smaller maps and tons of unlocks and pay to play content to line the EA pockets.... we shall see what way they take, but BC2 does not look like it supports mods, not sure if it would make sense at this point for DICE to include mod support for BF3.
Its all speculation until something is announced officially.