Remove senna from support, she is just a niche pick.
Swap either Vayne or KiaSa (They have similar playstyles) for Ezreal or Mf. You are missing a spellcaster ADC.
Midlane I have the most issues with.
Lb, Kata and Yasuo all require quite a bit of skill and champion knowlede to use well.
Swap them for Syndra, Diana and Talon.
That way you have a burst mage, ap assassin and AD assassin. Rather than 2 AP and one AD assassin.
Jungle is pretty accurate.
Id just swap rammus for amumu and Kha for Rengo, but I those are all just personal preference.
Toplane is also a bit off, but I can see why you chose those champions.
Swap Vlad for Kennen
Darius for Garen
Fiora for Teemo.
They fit the same roles, Ranged ap teamfighter, Juggernaut and split-pusher.
Kennen is more reliant on having the pressure early, since his scaling is a bit less reliable and he needs better timing on his ultimate.
Garen does hava mana issues and no complex abilities. His skill is entirely the decision making rather than champion mechanics.
This might be the weirdest one. I swapped fiora for teemo since they do the same thing, try to win lane then splitpush the rest of the game.
The difference is that Fiora can win a 1v2 lategame quite easily if the player is good enough, while Teemo struggles to 1v1 most top laners. Teemo needs more map knowledge to be an effective top-laner.