Thinking about deleting the "2.5D" concept page. Honestly, I'm a bit surprised it exists at all. Considering nearly all games are polygonal these days, it's enough to say that the game takes place on a 2D plane. A term for "this has polygonal graphics but has flat gameplay" is almost totally unnecessary. Graphical style and gameplay style are two things that, in this case, don't really need to be combined into one term.
Stupid term. It's up there with the incorrect use of "AAA."