TP cooldowns are there to help recover from death or AoE, and those are good enough reasons to have them in Raid. I'll pop Tactician when my melee dps are ressed and have been topped off accordingly, or to solve my opener aggro issues on BRD if I get a lucky string of crit and procs.

The real issue is there isn't a single TP based class that wants a lot of skill speed to boost its single target dps, so you rarely feel the need to have it. If we had a class based around, say, Empyreal Arrow style oGCDs, then maybe we'd feel the need to stack it. Even then, a class like that would want built in TP recovery in its kit and an actual skill speed buff rather than the haste buff we get now.