How I think ekko should be nerfed

I've seen a lot of complaints about ekko being over powered, honestly at this stage I think people just aren't completely used to or aware of his fairly complex kit which makes him seem even more OP than he actually is. Maybe I'm completely wrong here, I'm only silver 1 so I'm definitely not the best player in league.

I'm just about level 5 mastery with him now, many people have been saying he does too much damage but he's an assassin...What I've found is that he's too safe.

First his W, if he goes in and misses his W stun then he gets a very large shield to get out without any punishment and the mana cost on his w is incredibly low. Making a mistake like this shouldn't go unpunished, I think the strength of the shield should be significantly lowered to the point where I can take damage from a ziggs bomb, but also last slightly longer, or the mana cost could be higher, maybe a bit of both...Something that will encourage ekko to really pick the right time to use his W. Some might see a problem here where the shield would out last the stun, this would make jungle ekko more viable and it would also make him a bit stronger when up against an isolated target. I think this is good, it encourages ekko, as an assassin to isolate targets rather than face dive an entire team and tank the ones that aren't stunned for 2 seconds with a virtually impenetrable shield and I don't know about you but I like a champion with diversity so making jungle ekko more viable is great.

Now his R, the scaling on it is pretty high(I believe it's 1.3 ap compared to veigar's 1.0 +0.8 of target's) not only that, but it's aoe. However, this is not a very easy ability to land, I've had some success with it in low elo and also with people who were unfamiliar with his kit but using this in plat or higher I imagine would be basically impossible. Perhaps the most significant thing this does is discourage people from chasing you, but I also think this damage is quite necessary to help prevent people from camping your shadow. If his R damage does get nerfed, which would be horribly crippling to ekko I definitely don't think the scaling should be any lower than 1.0. Anyway, now to the real reason I am mentioning his ultimate...Again, I think it's a bit too safe, I find that it's up too often, I can always dive in, even under turrets thinking in my head if it goes wrong I can just ult out. I think there should be a higher cool down on his ultimate to encourage ekko players to be more conservative with it, it would also make landing that insane damage even more difficult.

Other than this, I think ekko isn't really that over powered...He's just a powerful assassin like leblanc or zed, actually it seems like the assassins are always considered the "OP" champions just because assassins tend to get fed.

This is just my opinion, tell me what YOU think, do you agree with me? If you were going to nerf ekko, what would you change and why? Or would you nerf him?

Thanks for taking the time to read my post :)