If we make it so bards can only use songs while singing, WHILE it is definately WAY more realistic, like I said, combat function goes way down. Then your in a dilemna of, do you make songs just super strong since thats all they can do? Also, there may be old Nexus players out there looking forward to playing a bard class that is at least similiar to the old Nexus bards.
It might make actual combat a bit boring for bards too since all your really doing then is singing, and the rest would pretty automated aside from moving around. Being able to sing to create an aura and then be able to attack with a weapon and cast for damage definately made for a fun to play class (while being fairly unrealistic) Altho perhaps it could be argued that the bard just weaves the spell chant into his song. And if you made instruments count as weapon types for bard, that might alleviate some of the unrealism, altho then your shooting arrows out of a harp and bludgeoning people with a lute, but it might work.
Instruments as weapons though also makes it so you have to add a whole new class of weapons for one class, and have them readily available as you progress, so it adds more itemization end for the coders as well.
Could also make bards really OP if you make them have a damage song, then all you would have to do is find mobs that dont have ranged attacks and just sing to do damage and kite the room around while you AoE everything down. With combat mechanics the way they were, if you did damage to a mob, it would turn on you, so if your on a group doing AoE damage, you would essentially be drawing everything onto you and causing the tank headaches.
In the original Nexus there was No AoE abilities aside from mobs, the mobs could breathe elements on an entire tile.
There is another thread about AoE damage, and I think the way Nexus combat mechanics work, AoE is PROBABLY not a great idea, so then you get in a situation of do you just make a single target damage song? that would be kinda weird, idk.