I am against. It is just too complicated. More mechanisms = more bugs and exploits.
Not not if done well. More mechanisms also involves more options.
If I got it right, low sequence and high sequence characters will have advantage over regular chars - low sequence char will spend less than half of his APs every time and high sequence char will try to keep his APs lower than half all the time. Doesnt seem too logical, but it can make things interesting.
If it was up to me, I'd use sequence to determine starting AP. So with low sequence one would only regen 2-3 AP when out of combat, when combat starts the AP regen to full at normal rate.
The problem is, that sequence is determined by agility and perception.
The second thing is, that fonline is derived from fallout series. Potentialy new players know fallout mechanics, but this one would be something completely new they dont know. The whole result of developing this project is to maintain fallout mechanism but also balance them into MMORPG, result should have been compromise so new players should find all things familiar but old fonline players should be satisfied with changes that improves playability.
Oh yeah, RT combat is so familiar to me from original Fallout!
BTW, how your sequence change will affect TB?