Holy warrior or arcane strike?

[Anium]

I'm starting a new campagin centered around an arena and this is my current build:

Fire elf Mage4 Duskblade 3 Abjurant Champion 3 Lawfull good

Str 16
Dex 16
Con 14
Int 18+2
Wis 14
Cha 10

Variants:
Domain wizard(fire) fluff reasons, and a fireball from time to time can't hurt.
Generalist elf wizard
Martial wizard

This is mostly set, now comes the tricky choices. Feats.

Power attack(warrior feat), Law devotion(1st), Knowledge devotion(3rd), Divine disciple(war)(6th), and for the last one i was doubting between arcane strike or holy warrior.  Arcane strike would give me more damage but take utility from me and i'm already channeling spells .

[Arz]

Do you need a higher hit bonus? If yes take arcane strike. The damage boost on holy warrior is down a bit since you multiclassed.