With Boom, I believe you are reading it incorrectly, you choose a spot within the red tiles, that then targets random enemies within 2 tiles of that tile.
Used it in SOD, it's rather hard to get more than a couple of targets into the zone. It destroys more as a single target, but it's clucky to use because of the 4 cost and no movement. You have to use the teleport talent to set it up, or double turns. Since you have to center ON a character, you can't aim it between characters. I was underwhelmed honestly. It's strong, but it's so hard to get AoE value out of it having tp prep one turn by saving NRG to use it, and to move her into dangerous tiles to set her up to use it without moving.
@jaimereupert4247 it really depends on what you're doing. A lot of tower content uses wall of fire to slowly burn down enemies. For fools' journey, you can use more of the direct damaging spells like meteor storm.
@Statistic189 Yeah, teams change based on the situation. There really isn't a one size fits all. I felt pointing out synergies so you could build those into your teams for the needed content was best.