Idea for Skaarl
Instead of copying Gnar's mechanic I think it'd be more fun/thematic to have Skaarl hide in a bush on the map and you have to go find him to re-mount him.
There could be an icon on the map showing which bush. This would be better thematically as he loves to fight and is just as bloodthirsty as sion so it's no surprise he'd want some action from all lanes.
Not to mention having mini games within a champion are always fun (Bard for ex) just seems like Kled and Skaarl are a copy pasta of multiple champions kit into one.
and 
chains
unmounted Q is almost same as 
Q
Q.
passive 3 hit bonus damage. except its an active & its attack speed not movespeed.
E attack speed and bonus damage.
Q attack speed boot
passive
W
empowered Q
W blood boil
W
attack speed boost
im not gonna name them all. there are ALLOT of AS boosts in this game. a bunch of champs with same ability
other AS boosts are 
need i go on?
E slash and dash
except kled's is better