I actually really liked Mass Effect 3. A couple years ago I decided to play all three games back-to-back, importing my save as I went. It took a bit to actually do it, but I still really enjoyed all three games.
And Mass Effect 3 probably had the best gameplay out of the three. ME2, while also still fun, felt a bit too streamlined - the nature of the game removed gameplay choices. Like where in Mass Effect 1, you had the RPG-like system where you managed different weapons with their own stats and the like.
I liked this a lot because sci-fi RPGs (AkA ME1) are amazing, but I can understand some not liking it. But ME2 took the nuclear option and just removed all sense of real choice. Sure, you can choose to use a shotgun or an assault rifle, but all you could do other than that was use the basic model for the majority of the game then sometime very-late game you unlock the better version. Stuff like this permeates ME2.
I still really enjoyed Mass Effect 2, but Mass Effect 3 improved on it in a lot of ways. I shall once again use weapon customization as an example representative of the whole. You can actually customize your guns! I mean, sure, it doesn't have all the different guns and RPG stats of Mass Effect 1, but ME3's mod system was an acceptable compromise that I found enjoyable. The gameplay was also just better, and while it would have been nice to have more direct consequences of choices made in the previous games, I found the existing consequences and acknowledgments satisfying.
Though I was ambivalent with the ending. I don't really get what some people were expecting. I mean, sure, lots of different endings based on your choices throughout the last three games would be nice, but let's be realistic. I can't think (at least offhand) of any choices offhand in Mass Effect 1 and 2 that would actually change the ending. They may change the way you got to the ending, which Mass Effect 3 did somewhat replicate through the war assets rating thingy, but why would these past small choices change how the game ends?
And in terms of the actual endings, disregarding the possibilities for the branching paths, I'm still okay with them. They definitely weren't amazing, but it still feels like a fairly satisfying conclusion. You (probably) saved the day and have ended the threat, but it's not without sacrifice and there's still challenge ahead.
I can definitely understand people not liking the ending, and people of course have different opinions on gameplay, but people claiming it's the worst sequel ever?
Really?
And it isn't like I didn't experience the hype so I wasn't missing out on that either. I just don't get why people say that ME3 is the worst sequel ever.