ME3 buffed a lot of stuff, with a lot of extra attention going into the combat and load-out upgrades. Problem is, every - and I mean that - other part of the game suffered for those upgrades. Reputation? Pointless. Critical decisions? Really aren't any. Side missions? Ridiculous time-sinks, with very few consequences, benefits, or challenges. Good characters? Nah, we'll just throw in some really, really bad stereotypes. After all, who needs a hive consciousness or a tank-bred super lizard, when you can have a generic big-breasted robot and a poorly-crafted macho Mexican?
Pretty much everything that made 1 and 2 enjoyable suffered. Yeah, their combat systems weren't as good, and I don't miss the stupid hacking puzzles or vehicle missions. But the combat was always just an avenue to advance the story. It was never supposed to be trying to build a story around the combat.
The plot was suffering in 2, but they basically just threw it all out in 3. Token acknowledgements of previous characters or decisions. Tech changes randomly throughout the games. They attempted to make meaningful scenarios, but the further you got, the more they relied on your attachments from previous games. They basically stopped trying, and just ham-fisted old characters in briefly, with no rhyme or reason.
Oh, and don't forget a bunch of mechanics that you thought were going to be important, but never mattered... if they did anything at all.
So many were upset about the ending to this game, but the ending was the best part. It finally signaled the end of a horrifically butchered game and franchise. Sorry, why would you even bother putting a competitive multiplayer in? Co-op I could see forced in there... but competitive? REALLY? The single-player suffered significantly for that decision, and it's tragic for obvious reasons.
I don't often feel bad about spending $5 on a game, but I honestly would have preferred the over-priced coffee.