Man City have walked all over almost everyone this season. Being beaten by Spurs, Arsenal and Man United... well... so are a lot of teams.
January transfers can often take a bit of time to settle in, to be honest I was surprised you got Tosun, as he was still in the CL, and was scoring goals in the group stages, you've got a CL calibre player there who will probably get better next season. You look at Sanchez at Man United, even he has struggled since he moved. Theo Walcott seemed to start quite brightly for you, but I haven't seen Everton play recently. So could be 2 very shrewd signings for next year.
If Big Sam stays (big if), I think you will get better next season if he is given support, I honestly do, I just remember earlier on in the season watching you guys play in the Europa Cup, and I think it was the game against Southampton on sky where you got thrashed and I thought to myself "deary me, this is not a cohesive football team, they could be in serious trouble here". If it was a one off, you can brush it off, but it was turning into a pattern. It is easy now to say it was never in doubt, that you were never going to get relegated, but you'd lost your main goal threat, you were struggling to create anything, and your defending was all over the place (and that is putting it kindly).
Big Sam has made strides forward in improving your defence, people can dismiss that and say it is because he has been ultra cautious, but then why didn't Unsworth do that? If he had, he'd still probably be in a job and not Big Sam.
I know what it is like when you've already made up your mind that someone is crap, almost nothing will change your mind, but he's not that bad, and with a bit of time he has actually got a good record out of getting the best out of good attacking players. I mean he is a pragmatist, like Mourinho, and he believes that everything should start from a solid defensive foundation, but with a bit of time and a pre-season, he will improve next season (IMO).