I’ve been running @TaliaParks blue team off and on for a while now and generally agree with you. It works together really well, but there is one situation that can give me some trouble:
A fully traited Gloomleaf in slot 1 can shred Shadow Hunter if you don’t get at least a reasonable board in the first few turns. You can forego taking skulls to save the reflected damage, but if you’re not collecting enough mana to fire-off the other troops a few times, you can end up in some trouble. No one in this team can directly target slot 1 (SH hits strongest, Behemoth is AOE and Druid is random), so even if you are doing damage with mana, a skull-heavy board can really tie your hands as you have to either sacrifice Shadow Hunter’s limited health by taking skull attacks, or leave the skulls for the enemy to hammer you with. Once I get the agile trait, that would help to preserve her life a little bit in these situations, but it isn’t something you can count on to work when you need it.
In general though, as long as you can fire Shadow Hunter at least once, this team is hard to beat. Fire her twice and you can’t lose. If she dies before firing once, it is an uphill battle, but you still have 3 troops with good synergy. I’ve built other teams that are as reliable in all situations as this one, but not one that both contains Valkyrie and is as fast as this.