Kobal, it's not enough.

The HB's HQ is a level 3 guild that takes longer to get than a SS's guild. Most cavalry are built in castles so they can't get the extra 1 exp from the get-go. The two exp they do get from an HQ gives them only +1 att/def (not 2). They do get extra morale/stamina but it's probably not much.

In any case a +6 attack bonus completely overshadows the benefits from a +1-3 exp bonus.

It's true that I could change the name to "Weaponsmith's Guild" and make a ton of units eligible for points. But since every unit has a weapon, it makes the guild criteria far too broad and flavourless. It's true that I could also build/destroy tanners, but frankly it's an exploit that neither I nor the AI will do.

I guess I'm ranting too much so I'll make a constructive suggestion. The bonus should be +1 or +2 instead of +6 and should apply only to swords. After all, what business does a swordsmith have making spear points and pollaxes?