Blizzard created their own engine, from the ground up, in order to make this game. They can improve it, because they made it.
BiowarEA took a 25% done, beta version of an engine made by another company, and tried to slap some coding duct tape on it to make what they needed for SWTOR. Then all of the people responsible for making it apparently were fired/quit. Now you have people with no "Hero Engine for Dummies" experience trying to just guess their way through using it to utilize their programming.
Surely you can see how these are vastly different things.
---------- Post added 2013-01-08 at 11:36 AM ----------
Any gear you equip during your sub will still be usable after your sub ends. You will lose the ability to equip new gear at that point however.