I think it's truly a problem of perception. Prior to IO's and the now ubiquitous "softcapped defense" on every build, Ice was a solid tank choice and a fairly common pick for teams. Power creep and the reinvention of tanking since Willpower and all the newer sets have made Ice seem like kind of an outdated, weak set. (especially since it doesn't have positional defense) When considered as a whole, it's a solid tank with unique mechanics that have somewhat under the radar tanking benefits.
It's a defense set, sure. But, you also have recharge slows, and movement slows build into two powers. You have a damage aura plus as you mentioned maybe the best auto-taunting ability with both chilling embrace and icicles running. You have a 40% enhanceable boost to hp which I believe can be made perma. (never tried) You also have a very fast recharge aoe endurance drain which significantly helps with running all the toggles. And, the once unique to ice, hibernate. I would take hibernate over most other tanker primaries just because it basically ensures you never die and can without consideration refill health and endurance at will. There's also something really iconic about freezing yourself in a block of ice to heal and recharge during a fight.
I think despite it's old age, it's still a solid tanking set. Most people probably won't even consider using it because all City of Heroes' perceptions are strongly influenced by mids' builds and the God awful farming obsession that has taken over since brutes and the AE. I guarantee you can make it strong enough for any team to tank just about anything.