"If you're using a weapon that's really good at shooting at your own feet FAST to get out of a bad spot, you can do without (fast shooters, inkbrushes, sploosh, etc.) If you're running long range (chargers, even SSP, squelchers, etc. you probably shouldn't hope to need it, otherwise you're probably playing inside your zone. If the enemy got close enough that the ink is a problem, you probably aren't going to make it out in one piece.
Rollers, octobrushes, and the slower shooters (gals, etc), blasters, really need ink resistance IMO. they'll tread a lot in enemy ink or have enemy ink spread around them and have no way to easily break free."
I'm sorry, I don't know how to quote but this!
If I have a weapon that is a fast shooting/moving weapon I find that I don't need ink resist. On weapons that shoot slower or that I need every shot to count (for me that's blaster, gals, and pro to an extent) than I really don't want to waste time painting my feet for that one little patch I got stuck in. Other than that I only seem to want it I'm trying to flank and I'm getting slowed down by random patches of enemy ink but that seems to not happen very often.