1) If most of us "have to" dispel, then isn't a talent that makes it cheaper and tosses a free heal on top of it strongly recommendable? I fail to see your point. It's just semantics.
2) Ancestral Resolve is not useless. It's a survivability talent. But it's unappealing because there are still alternatives that will, on most fights, save you Mana and heal more.
3) Yeah, okay, if you happen to be banging your head against the one fight that removes the need for Shamans dispelling, maybe ICS and CW are not needed. But that's true for what, 0.1% of the Shaman population? That still makes ICS and CW two eminently recommendable talents.
Going to have to disagree with you here Amilie, In both of my specs I have not opted for CW, it is simply not required, the heal is very average, and the mana cost is very meh.
There are far better places to be putting 2 talent points than in here, AR is certainly one of them. Of course this does totally depend on your raid setup and what you are raiding, ie 10s vs 25s and HC vs Normal. If its 10's then yes perhaps worth getting as you will no doubt be called upon to dispel more. If 25's then not so much. If its HC's then you really do want to be going for AR, that dmg reduction is extremely useful and as you mentioned saving mana and healing more, this means you dont have to pop and extra heal on yourself because you have saved the inc dmg, thus saving mana anyway.
It does therefore totally depend on your own circumstances, if you are in 10's then maybe go for it, otherwise others are better.
Think of it another way, there are not that many occasions each fight even under the best of conditions when you might dispel things, many fight require no dispelling at all. However you will always take dmg and reducing this is far better in my opinion.