Or simply make better bows for heroes. With the exception of the OP lightening bow, (+2 lightning damage per lvl) they all suck. 

Fine, so thats two bows that don't completely suck.

So now we're up to 3 bows being good. Any more?

heroes already use special versions of items (with relatively large gold cost) i cant see any reason why this special versions can't have different stats.

The Perfect Yew Longbow is really nice for a hero bow, using it on Lith Serrata in my current game and she was all kinds of nasty with it through the mid game.  Late game, I have armies stacked with high initiative units and I rarely get more than one action from my champions anyway.

I like the idea of making hero weapons better than the non-hero versions.  I generally avoid bows on my champions because of the huge initiative penalties, which slows down spell-casting. The Perfect Yew Longbow, with 22 attack and only a -2 initiative penalty is really the only bow that I consider good enough, and I've only ever seen it once.

so, maybe it's not a matter of 'they're not good'....maybe it's more of 'there are not enough'

Maybe some of the higher bows should be moved from ultra rare to uncommon-ish?

I did play as an archer Assassin (yes was with Tarth, but believe it or not most of your damage in a battle comes from normal shots). What can I say, at start is a pain until you get a better bow (if you're lucky to get the Ignyss quest, is fine, otherwise not so great). But then it starts to catch up as you hit shadowstrike and get better bows.

The initiative is also becoming a non factor past early game (all higher rank bows have lower penalty on ini and you can use mounts that increase it, as well as accessories).

What I wish is for another skill for the archery heroes. Just shoot and Rain of Arrows doesn't really compete with other weapons who have innate skills. Maybe add a skill that dazes the target? Or roots it in place for 3 turns.

It has a cooldown of 5 turns. Just because you act more often during same turn, this does not affect the abilities cooldown. A game combat turn passes when every single unit played an action. I tested this with a level 10 air / water mage (with my air power I was getting 10 initiative boost from haste) going solo against an enemy scout. I slowed him and hasted myself, then cast wraith touch. It didn't come back off cooldown before scout took 5 moves.

Not to mention archery is easiest to defend against with aeromancy and air disciple (not to mention any innate dodge a unit / hero may have). There is nothing you can do about it unless you cast growth on the unit (which really isn't optimal lol).

Well, this actually helps to keep the balance

Haste allows you to act more often during a turn, not to get more turns, same as slow delay your actions until end of turn, not prevents you from acting for X turns.

Think of it as an army with 2 movement and one with 4. Both move once during their turn, but one travels further

I've never seen a magic bow that did more than 9 points of damage.

I think that hero equipment needs a buff from what normal foot soliders are equipped with.  It's supposed to be hero gear, so you'd think that they'd get masterwork version of things.  Or simply have those available as well. 

Breaking out the different stuff into tabs in the shop sure would help, too.