The fact that Sprint penalizes just DoWs is weird. It should either penalize all classes (costing a chunk of your primary resource) or none.

Personally I'd lean towards it being free, but possibly nerfed, such as giving it a 10 sec duration in combat but up to 20 sec if used outside of combat (and you don't enter combat during its duration). Or increase its cooldown in combat or something.

If it instead did drain primary resources from all classes, even if you took away most of a THM's MP, he/she can get it back. And a CNJ or SCH would never be allowed to sprint in combat if it drained their MP, that'd be suicide.

I guess another option would be to lessen the TP cost. Maybe do something like spend 100-200 TP for a speed boost for X seconds, and if used again during this duration, drains all remaining TP to increase its duration.

But Sprint aside... I'm still not keen with how some DPS classes use a long term resource (TP) while others (THM) use a short term one..