Right. Well. I've beaten both Grym and Mrs Toll the gold fashioned smack 'em to death way, using the rules. And, that proves that you can totally do it your way. I don't see an issue with others doing it differently. I don't have the patience for stacking the crates either, but it's good fun for others.
Regardless. They are optional boss fights. They always come with some sort of gimmick or other. And, in typical D&D fashion; getting creative with the rules. In tabletop, everyone always tries to teleport to the end of the dungeon, or fly to the top of the tower. It's always been like that. I find it rather amusing that this game addressses that sort of gameplay instead of invisi-walling you out of that.
It's not new, either. Going up against Firkraag without protection from fire and fear meant you died. Running at Kangaxx with no protections up meant your death. Or, Imprisonment, really. Unless you're a Berserker. Heh, in the old one on Hardcore. Just 'the rules' - meant a Fire Giant will crit you from 130hp to 0 in a single hit. Balors and Divas with Vorpal hits, multiple mages casting Malison and Chaos ensuring none of your people are responding to commands and mudering the local townsfolk...
A boss one-shotting you isn't anything Larian came up with for giggles. It's just always been a part of it. It means you stay the hell out of melee range and come up with different tactics.
And let's face it. It's 5E, there's tons of options - it's not hard.
