Cleon
Legend
Well, based on your line about the great falchion, we'd best keep Weapon Focus anyway.So Power Attack, Cleave, Weapon Focus (falchion), and Imp Crit (falchion) for the fighter feats? Does that do it for the chieftain? I guess we need to calculate initiative, which would be +4 with Imp Init, I believe.
You fell into my Precisely Focused Weapon Shot trap.
Bwah hah hah!

However, I would point out you've given the Chieftain Power Attack twice, as it already has that as one of its Giant feats:
Feats: Cleave˟, Improved Critical (falchion)˟, Improved Initiative, Iron Will, Lightning Reflexes, Mounted Archery, Mounted Combat, Point Blank Shot, Power Attack, EVEN MORE Power Attack˟, Weapon Focus (falchion)˟
7 feats plus 4 fighter feats˟
So how about we give it another feat from the POWER ATTACK CHAIN instead of the surplus fighter feat Power Attack? I'm leaning towards Improved Sunder.
Feats: Cleave˟, Improved Critical (falchion)˟, Improved Initiative, Improved Sunder˟, Iron Will, Lightning Reflexes, Mounted Archery, Mounted Combat, Point Blank Shot, Power Attack, Weapon Focus (falchion)˟
˟fighter bonus feat
Anything else on these?
Well I guess it needs a brief description and maybe a few words on tactics, but mechanically it's done.