no comments on blizzard, some people love to use them till end game.
most wizards uses diamond skin, unless you are very lucky in loots you're so well geared you dont need to run on diamond skin. but then again, it's different for certain people

force armor is useless in inferno, if you need that it means you're not good at dodging/kiting or to position yourself in your game. but then again.. it doesn't really help too.
reason is that it doesn't work with most elites, neither bosses, try stand face to face with a boss elite with FA+diamond skin, brag about if if you can take at least 3hits.
*FA doesn't work for desecrators, poison pools, basically all the DoTs too.
secondly, mobs especially in act2 onwards, they dont deal damage in 1hit count, u get like 3slash combo, spiders and lacuni will give you multiple hits in a matter of seconds.
thirdly, you dont walk 20yards and get 1 mob in inferno, there are HORDES of mobs everywhere, if you're going to get hit/ganged by mobs, you expect to take maximum of 2-3hits? what about ranged mobs?

prismatic armor works even better when you have higher resist, true that. but if you only have 50-100 resist, you're not even fit for inferno yet, dont need to say which rune will benefit you better with your low resist.

I guess it really boils down to individual preferences. Some people are comfortable with kiting, some prefer to tank. I personally disagree that most wizards use diamond skin. I know plenty of wizards who don't and do well in Act 3/4, with decent gear (not superman level of items).

I wouldn't call force armor useless either. I ran with it in Act 3 pre nerf, when I had really bad gear, and I used Illusionist too (which you mentioned was not worth it, iirc). It got me through Act 3 just fine. DoTs really should be avoided, that's all there is to it. Desecrator doesn't tick immediately, poison doesn't kill immediately. Those cases where you get jailed in a desecrate is another issue altogether. Force armor is really for those 'oh crap can't dodge' moments, and being able to take a hit rather than falling over dead the moment a mob breathes on you is always worth something, no?

Otherwise, I tend to agree that you shouldn't take hits as a wizard. Melee wizards, meh. Roll a barb, guys.