This isn’t really up for debate anymore in my opinion. It’s obvious that as part of a dedicated team, Miko is insane. If you all ever start up any kind of ranked/competitive/esports play Miko is going to be on every team. Pair him up with a good tank or melee character and they’re just too effective. It’s hard to even so much as focus Miko down as he’ll just jump around and play evasive while his partner wails on you.
There’s a couple different ways you could fix Miko (in no particular order).
1 - Give his heal beam an energy pool. Make it so he fires the heal beam and eventually it runs out of energy and needs to recharge. This way he can’t just infinitely heal while you’re trying to take him and his partner out.
2 - Make him a lot squishier.
3 - Lower his heal rate. At his current rate he can heal a character up to full health in only a matter of seconds. Put his heal rate closer to the rate of a supply station, it should be better than a supply station, but only by a bit.
4 - Make his beam something you actually have to aim, more like a laser beam. This would make it harder for the Miko to keep up the heals if you are attacking him. Yes, his partner could still wail on you but he’d no longer be getting healed by Miko while doing said wailing.
I’m sure there are other ideas out there, these are just a few. Regardless, one way or another something needs to be done to tone down Miko’s power as part of a duo.