I find the Glade Guard Longbow argument rather stupid. To argue that all models in the wood elf army should have the same bows as the glade guard use, that seems almost insulting to an army that is renowned for having its greatest strength honed in its diversity. An army where each part has a particular role and in which each has adapted its equipent to suit it. For example, glade guard classically have the role of pouring fire into enemy ranks while maintaining a constant flow, causing the enemy to find targeting them from afar difficult. Thus, i believe this profile should be accurate;
*No Move vs. fire penalties
Possibly coupled with the idea that glade guard should be at -1 to hit from shooting attacks, this would create a mainstay unit that is quite rightly out at the heart of each wood elf army.
Glade riders on the other hand are differant. There role is to ride through the enemy, using shorter range fire to inflict causalties before charging from an unsuspected angle. So, there bow profiles should reflect the need to deal high strength damage, but not nessacarily does there fire have the air-time to gather velocity to penetrate armour (that, or they cant accuratly aim for armour joints and vunerable shots while riding a horse to the same extent as a foot soldier can). However, in a similar way to persian or mongolian short bows, there fire shoudl have higher natural power and reload rate. But, while riding a horse, the ability for a rider, even an elven one, to move seamlessly and fire withoit penalty is a bit far fetched, and thus it is not going to be (as already noted) as proficcient as a footman. So, something like;
*Quick to fire
The elite (ie waywatchers and some charecters) should have incredible bows, adapted, honed, enchanted and pefected to match there skills. Thus, their bows shoudl hold the power of a glade rider bow, the speed and armour piercing of a guard bow, with the added skills associated with there fluff. Sniper and killing blow spring to mind (with charecters having heroic), however the balance of this when coupled with scout could be tricky.
Aside from bows, anouther simple change I would like to see is the improvment of durability for treespirits. I would think an imporved save system woudl be warranted. Dryads being teh weaker of the three, should be equipped with a 6+ ward save (that can be taken against magical attacks). But, they should also have a 5+ armour save. For each consequtive branch of the forest spirit (treekin-treemen) there should be an increase of one in each save (Treekin = 4+/5++ - Treemen = 3+/4++). This staggered approach has always made sense to me, and is a concept that I believe is practical and also balanced.
Finally, as a small change, parry being introduced to eternal guard, possibly at a 5+ value, woudl make sense, and fit the way they fight well.