You should play SAM. Their Kenki gauge is exactly this. Almost all their oGCDs are tied to kenki which you naturally build and expend. A lot of people lost their shit over Iaijutsu and 1000 potency Midares but in practice their major kenki dump, Hissatsu: Shinten takes the potency edge over Iaijutsu.Now that I think about it more I wish they handled TP like Blade & Soul handles Focus.
Basic attacks don't consume TP but refill it. You also have a but load of moves that consume TP (some spammable oGCDs and some not spammable oGCDs) that you have to balance out with moves that allow you to regain more TP.
This would end up with more oGCD usage which is good because I dislike how half of the combat is on long minute/multiple minute long timers.
The 2.5 second GCD time on weaponskills wouldn't even be a problem if the game filled the gap with frequent oGCD usage.
That's why it feels so fucking slow at low levels especially. Because all you have is one weapon skill > 2.5 seconds later > another weaponskill > 2.5 seconds later > first weapon skill again > repeat x9999.
TP feels even more archaic now since it's not even an issue most of the time. The only time that you might run out is on long AOE pulls where someone isn't pull their weight causing you to run out.
I'd rather TP be something you normally engage with in combat like B&S focus.