I wish they didnt attempt to be smarter than they really were. that is the core of the problem of what we got in ME3, plus most probably unreasonable time limits imposed by the EA.
I think many people writing scifi be it for games, books, tv or movies underestimate endings that do not try to jump sideways. I liked Reapers back when they were huge sentient semi-organic machine squids. Subverting people with their indoctrination, thinking themselves way smarter than anyone else. The kind of enemy you relish beating, relish that moment when they fall because of something you did. Starbrat took that away. Reapers become inconsequential, in fact if you replaced reapers with pretty much anything else it wouldn't matter much, Reapers were iconic when they were each a nation, arrogantly disdainful of organics, so dismissive of the potential threat to them. Now? Now they are basically the same as those mechs we kept fighting in ME2, the only difference was in scale.