Best thing to do is add up the profession bonuses.
Obviously I have no idea about rogue stat weights in Cata, but assuming Agility is the go-to stat, here are some pointers.
JC allows you to socket 3 X Delicate Chimera's Eye gems, each giving 67 Agility.
The regular non JC red agi gem grants 40 agility. So each JC gem is 27 more agi, thus the overall bonus from taking JC from a pure dps point of view is 27 X 3 = 81 agility.
You may want to consider Leatherworking. I know for rets that LW is looking like top dog dps wise, and for rogues the LW bracer enchant provides 130 agility. The other bracer enchant options for non LWers are 65 crit or 65 haste. Str for ret pallies is so ludicrously better than either that it is the obvious choice. For rogues however I have no idea - IF Agi is miles better than any other stat, the LW is probs gonna be top, if not, well you will need to spreadsheet it.
Enchanting provides 2 X ring enchants - each granting 40 agi, for a total bonus of 80 agility.
As you can see you have quite a few options, and they are all pretty similar in terms fo dps increase - 80 agi from ench Vs 81 from JC - go figure.
The real issue will be whether agi is so much better than crit or haste that the LW bracer enchant is simply BiS. I cannot answer that - you'll need to keep up to date on rogue theorycrafting to find out, and we probs won't know until Cata is out and the rogue theory bods have properly sat down and worked it out.
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