Baldur wasn’t a bad hero before, but now with recent buffing (increasing damage to 150% and random attack on activation) he is a beast.
Here’s the reason why Baldur is good:
With modern buff duration, it is quite common to have buff/debuff that lasts 2, 3 or 4 turns. If you want to use those buffs/debuffs, you’ll need to time your specials or tile attacks right, which is usually quite hard to do.
For example, Black Knight buff is very powerful (up to 145% attack increase), but it only lasts 3 turns, and you can have hard time collecting tiles or fire your specials in that 3 turns. Same thing for defense debuffs, they usually are for 3-4 turns.
Baldur hits every turn after activating, so he can hit 4 times under Black Knight’s buff, each hit will be 300-400 damage. You don’t need to worry about timing anymore. All you need to worry is to protect Baldur from direct sniper hits, which BK does automatically.
There is also one problem with Baldur - if an enemy has Black Knight activated as well, Baldur will attack random heroes, and if he hits heroes other than Black Knight, the hit will not deal any damage.
I think this is the same for Queen of Hearts.
Stonecleave and Ameonna can also make Baldur miss.