One of the annoying aspects of SK is that you end up with oodles of weapons and no-one to give them to.
As far as I can tell the only character you can provide with a weapons is your initial champion. Every other character referred to as a "champion" is in fact not. So when the minor factions give you their champions they are just regular units.
This is a bug, over sight or have I missed something?
This is confirmed as a bug, see the latest dev stream. I think Stardock forgot to add a skill saying the Remnants Heroes can equip swords etc.
Further you can also get Heroes by "questing" e.g. they can be found the map.
So you have three types of heroes.
1. Your starting hero. Usually ok
2. Heroes you find on the map. Varda, Necromancer, Keplin etc.
3. Heroes you get from the Remnants, when you are allied with them. They are lesser powerful and also both have advantages and disadvantages. For examply you have a hero who knock backs enemies everytime he attacks. Further he needs to get hit to get power so he can use his skills. Unfortunetaly you do not want to get hit, so this hero is pretty useless. The Swamp hero Adam Swampy has splashing damage damaging friend and foe alike.
Heroes from group 1 and 2 should be able to equip weapons, while the heroes of the 3rd are bugged.
I also think there is a 4th group being heroes you get via the Sovereing Skill tree. However I think only the Priest has a skill, where you get a Scoundrel Hero. But this does not work as I did not get a hero. This makes the Priest pretty useless. 
