I have a few board games in the collection that fall into this category.
For ex;
1) Ank (+ it's expansions) - I backed the
KS for this. I think it looks like a decent enough game. And the
KS came with all kinds of cool figures vs just cardboard tokens. A pretty good deal for the $.
But it turns out it's got way to many rules & moving parts for most of the people I play boardgames with. :(
I really don't want to explain the game once or twice per turn....
On the + side I have a whole bunch of Egyptian themed minis for use in our D&D games at a very reasonable cost per model.
My regret here isn't the $ spent. Or that i wont use it.
It's that I'll probably never get to play the actual game.
2) Last year I picked up a game called Offshore - a worker placement game about drilling oil wells. Sounded interesting. We like worker-placement stuff. Didn't sound like it was
too complex.
Gameplay turned out to be a dud though. Not unplayable bad, just several of us simply have better (and prettier) stuff in this category already in our collections.
The regret here is spending the $ on this vs several more trips through Starbucks.