@Holotor : Well gettin a better MMR is normal , on you alt you don't do error you did on you main.
@Chab :
Azir is so f*ckin usefull as an offtank, play it like you play Swain , RoA then you have to choose an item for the matchup (Zhonya for counter ult like kata or zed one , Rilay against an AD midlaner , Abyssal against an AP one) After that get some Several HP (If you don't have rilay , get it) Then you will be hard to get shutdown...
Per exemple , on your matchup (Azir Vs Talon) you better get zhonya after you RoA then get rilay and start building flat AP.
Here's some word of wisdom that a friend who is challenger give me :
"Noob champs doesn't exist , They are all balanced and they all can be powerful if you play them well".
Well i don't know about the translate , we're both french and i have to translate this xD .