Because secondary stat budgets are now doubled on gems, this changes the way we slot our sockets. If we have a secondary stat that is weighted more than half of our primary stat, we are now supposed to gem pure secondary stats in blue/yellows, and hybrids in reds.
The JC exclusive gems were not given double budget for secondary stats, so we're still stuck with pure reds for JC gems.
However, this 320 extra stats from JC gems requires a red gem in a red socket. This would have been fine if we were gemming pure reds in red sockets anyways, but now we have a better option in the form of hybrid gems with double secondary stats. To obtain the JC stat bonus, we forgo the superior hydrid gem in favor of pure reds.
Because of this, the relative gain of using JC gems is LESS than 320 stats.
To fix this, the best option would be to provide hydrid JC gems that provide extra primary stats, such as +240 (80+160) strength and + 160 haste. This allows us to gem hybrid serpent's eyes while still obtaining the same +320 stat bonus standard on professions.