The problem with EQ is the frequency of change, and expansions. If it were a simple matter of making a handfull of changes every 6 months we would be doing that... But since it requires a complete rewrite at almost every patch date, we're in a tough spot.
If Sony ever slows down the release of new content or (shutter to think it) they deside to pull EQ as a supported MMO, we might at that point be able to get our hands on a good client to use that we know won't be altered.
The other problem is that they've been adding things to the game that we can't easily copy. Instances, monster missions, spirit shrouds, all of these things plus more can't simply be turned on... they require planning, and designing that Sony has a full team of paid coders for
