Your assumptions aren’t correct.
No. The only games you can get here are Epic games which simply don’t need any additional options. All you need here is Install/Play button and News links. Especially for staggering amount of 2 games in active development 
And there’s a tab to download custom game editors - it’s for modders only.
Developers use launcher quite often to download and update plugins, content packages, learning samples. It’s the only way to install engine, change version or installation option.
I use UE4 and play Fortnite. I don’t see any need for changes you described. It’s not a Battle.net