Which archer is better, a Battanian fian champion or a dismounted Khuzaits khans guard? I wonder which one it is because I know that they are both the only tier 6 troops with bows, and wonder which one would be a better archer.
Note that this game is in early access so the end result can still change, but as of the Beta 1.3.0 patch, here are the stats for each. You can see this yourself by opening the spnpccharacters.xml file inside the Modules/SandBoxCore/ModuleData folder of your MB2 installation:
Battanian Fian Champions: Athletics: 200 Bow: 260 TwoHanded: 220 Equipment: Woodland Bow(longbow/yew bow 72/60 damage, 94/92 accuracy), 2 stacks of Bodkin Arrows, T4 Battanian 2 handed sword Khuzait Khan's Guard: Athletics: 60 Bow: 260 Polearm: 220 Equipment: Composite Steppe Bow (62 damage, 94 accuracy), 1 stack of Steppe Arrows, T4 Khuzait Polearm
Without the horse, it is clear that the Fian Champions are superior archers as they carry 2 stacks of arrows and have much higher athletics for maintaining distance while skirmishing.
The only slight benefit of using the Khan's Guard in dismount form (i.e. in seiges) is that polearms have a little better reach than the 2 handed swords.
Armor wise(I didn't bother listing them) they're both about the same, with battanians having slightly higher torso armor and khan's guards having better arm armor.
Of course, you are completely disregarding the main benefit of the horse archers, which is the ability to be mounted so they can pretty much avoid charging enemies with ease while the Fians have to be a little more careful against enemy heavy cavalry. Also having an entire army on horseback gives you much higher movement speed on the campaign map so you can pick and choose your fights.