A treant would be able to beat the crap out of the Redbrand Ruffians, but yes, I get your point in general. I felt the same way about the initial Elemental Evil lairs in PotA - far too mundane. I wish they'd gone with the way cooler ones shown in the concept art at the back of the book.
I'd really love for WotC to do something truly fantastical ... like a world split apart by magic, where everyone lives on floating earthmotes and airships / teleportation circles are needed to get from one earthmote to another.