I leveled up my Sienna using Unchained, and then swapped to BW only fairly recently. I don’t consider the overcharge management to be particularly difficult, just a chore and too risky when I typically go into melee range with very high overcharge. I don’t want to have to worry about casting too much before going melee. One unlucky AOE and you splode. I think if the ult cleared her “about to explode” status it would be a little different.
BW has passive abilities that gives ranged power, passive venting, and ranged charge speed on high overcharge.
I typically run my BW like this for talents:
Stamina +1 (more block+attacks, my favorite with mace)
Power stacking (note that this is not melee power only)
Reduced block cost (defense and more block+attacks indirectly)
Health on kill
Firewalk removes overcharge
So here you have ranged and melee power, defense, and utility boosted with an overcharge clear. The teleport has mobility, aoe knock back, and damage over time. Not a devastating killer, but very useful for lots of things. Mobility, escapes, kiting, reviving during hordes, saving people who are cornered, you can get really creative with how you use it. The skill cap is high.
I would say Unchained has more defensive talents regarding Stamina, overcharge, blocking, and health, with the power boost only applying to melee and only when you’re very high on overcharge.
The ult is no doubt much more damaging, but I prefer the mobility of tp as a personal choice.
I still maintain that BW is a mix of offense and defense with utility, a more versatile hero, while Pyro is ranged dps and Unchained is tanky. I don’t find BW awkward, just not as focused on one role.
I definitely feel like the proximity power stacking & teleport would be great for Unchained, there’s definitely some strange overlap of roles there.