Recently I won 2 ranked game and instead of gaining % towards the next rank I lost % why is that
Demotion protection.
Same reason I gained 130% on a win recently.
Looks silly, but nothing wrong.
Blizzard have no clue about how to work MMR. It’s the same for World of Warcraft too, it’s complete dire.
How would you fix it. Or what alternative would you use?
May I remind you that it isn’t my job to elaborate such information. This is what they get paid to do, not myself. 
MMR is broken on WoW as well as OW. It’s either stomp or be stomped, and has been for quite some time.
I am just curious as to what sort of system you think would be better.
That’s the nature of ow. You aim to stomp. You don’t want to give the enemy time to breathe.
Again, not my job.
There’s a difference between playing a fair great game or being completely stomped. Which means the MMR is problematic. 
If you’re given fair games pretty much every game, but one team just makes better in match decisions which leads them to stomping the other team… That doesn’t mean there is anything wrong.
Or… We can just blame everything else and not take responsibility for the things we do in game I guess.