I think the general rule (according to most theorycrafters) is that 1 spell crit = 0,7 spelldmg, so the 40 spell dmg will outweigh the bonuses you'll get from 30 int. Most important of all for raiding-Mages is spell hit though (until you hit the cap), that's why those gloves you got are a bit better than the ones you had. Especially if you enchant them.
I'm not really a Mage expert though, just saying what I've read and heard.