Champion kits are being hold back

So recently i noticed that some newer champions kits are not fully controllable as they should be.

First example is Tahm Kench.Started a custom game to try him out.Before playing i read up on his kit what can he do.So i was like hmm he could work nicely in the jungle. Then i got slapped in the face when i couldn't devour big monsters.What is the point?Isn't this exactly called burden of knowledge?Putting that aside why is he prohibited to use W on the buff monsters??It artificially reduces his ability to jungle.His kit would be superb after lvl6 for ganks but it's not that great as his clear speed is being hold back with this gimmick.

Second example is Ekko.Again when i tried him out my very first action after i casted Q was pressing Q again to call back the projectile.But it didn't come back. Then after playing him more and more it got even more obvious that his kit lacks this callback ability.It would be a nice way to clear waves faster but have to fully wait out until the projectile comes back.Also this way it won't hit every minion while they are in line.Again a gimmick holding back the kit.

I feel that i don't have full control over their kit and i was wondering if there could be changes made to avoid this.As i don't see any reason whatsoever for these weird interactions in the champions kits when they could have been implemented and balanced along.

I am pretty sure there are more champions that have similar problems.