The two armour items that you can craft are really nice for a Frost mage. Haste is so win! Of course, taking twice as long to make Glacial Bags isn't going to bother most people, either.
What is annoying is that your cloth is going to be the least sought after, meaning you will not benefit as much initially as Ebonweave or Moonshroud tailors. This may, however, be balanced out -- at least for a time. See, a lot of people will be going Ebonweave or Moonshroud because you will benefit from making 22-slot bags more easily, and providing for the only two cloak enhancements that tailors will use: Lightweave Embroidery and Darkglow Embroidery.
So, it's a question of whether you think you will do better by selling 22-slot bags and providing the other two cloth types for players; or whether you think it will be worth making your own robe and gloves and predict that other people will call on your services for their own gear: because they went the path of the former.
After looking at it, Spellweave Tailoring really isn't that disadvantageous -- especially considering that you will be able to make your own armour and not have to rely on someone else choosing this specialisation. Also, I'm sure that in future there will be other additions to the game that require any of the three cloth-types; and I'm sure that some of these items will be very nice and require Spellweave.
Too bad all tailoring is crap except the cloak. Then again a Naxrun and the cloak isnt good either. Tailoring stink in WOTLK.
TBC had too op stuff like FSW but as always (palas will 'smile' now) when BLZ spots smt that is too good they dont just set it to a proper level, they set it way lower. Tailoring in WOTLK is not an exception.
I will dump my tailoring as soon as i get a chest better than my sunfire robe to get some usefull perc, yea im a raider ;o