Bows are a ranged weapon, if you let the enemy close the distance on you, you are at fault for giving your advantage away. In saying that, foot archery in MO2 is a meme in most situations. They're an initiation for group fights, stickying a mage down, or dropping mounts.
Just like mages, archers have to learn to gauge time correctly for their actions and if an enemy is closing in. Do they have to time cast, draw bow or kite back? It's something you need to learn. You're better off pulling out a melee weapon before the enemy reaches you, instead of trying to get greedy and letting off one more arrow point blank.
The realism argument for allowing bows to block, is kind of silly. Long bows, compound bows etc Would either be whipped out of a persons hands if trying to block with them, or be cut right through before the blade splits the users head - Either way would result in death. The density of bows and their wood, mixed with their weight is not strong enough to withstand heavy metal weapons with high velocity. There are mentions in historical records of archers using their bows briefly as a melee weapon to hit their opponent, to give them enough time to draw their melee weapon, though I would't imagine a bow doing too much physically to an armored opponent, either in plate, mail or a gambeson. A crossbow how ever would probably stop or deflect a blow from a lot of melee weapons.
In saying that, realism for the MO universe is kind of weird since a lot of things go against realism, which comes with the territory of a fantasy-esque environment.
At most, allowing a bow to block 1 or 2 hits before breaking and mitigating like 50% of the impact damage would be fine I guess, but not sure if that would be useful. Same with implementing some kind of basic melee feature to briefly use a bow to slap someone, though would be akin to using a wet noodle unless person was naked.