If each TP class (PGL/LNC/GLD/MRD/Archer) had skills that consume large amounts of TP for big effects/damage while executing combos
replenishes additional TP (10tp per successful combo skill) then TP might feel more important.

Example Pugilist:
Holy Fist: Delivers an attack with a potency of 250
Additional Effect: Heavy
TP Cost: 300
Recast: 30s

Death Blow: Delivers an attack with a potency of 100
Combo Action: Touch of Death
Combo Bonus: Consumes Touch of death DoT effect and deals 8 potency for every second remaining on Touch of death. (Max: 240 potency)
TP Cost: 450
Recast: 30s

Example: Archer
Haymaker Arrow: Delivers an attack with a potency of 600
Cast time: 5s (Moving will reduce potency based on how long the ability was channeled)
TP Cost: 600
Recast: 30s

Example: Lancer
Visceral Thrust: Delivers an attack with a potency of 100
Combo Action: Vorpal Thrust
Combo Bonus: Delivers an attack with a potency of 400
TP Cost: 500
Recast: 30s

p.s. Bloodletter could restore TP for Archers since they don't have combo skills.