We already know what most of the gems are.
http://www.capcom-unity.com/brelston/blog/2011/12/14/street_fighter_x_tekken:_standard_and_pre-order_gems_listed,_explained
The pre order ones are basically the more powerful versions of the default gems but with no drawbacks. That is complete ass.
But at the very least Seth Killian says that if the gems get a big enough negative reception (through don't they already?) they will add a filter for them.
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http://i43.photobucket.com/albums/e373/Gaiash/KumaVsZangief.jpg
LOL!!!! I hope that's a joke....names don't get more n00bish than that