They zoom it to only show the champion itself like on the loading screen.
That way it is questionable whether such concept has a point If the other one won't be properly visible.
A lot of the skin lines do this. For example, the Baker skin line, the URF skin line, the SKT/Fnatic skin lines, etc.
Their loading slices may be focused or enlarged, but the splash arts are not (that is, If my memory is not tricking me). The maximum they do is flip some of them (mirror them). And the reason this works is because most of them (not really sure If all of them) are standing together as team, while Morgana and Kayle in this splash art would have to express hostility towards each other in some way.
However, good you mentoined the skin-line group splashes. It reminds me of Pentakill one which indeed is not focused enough which is point for you. And as I am looking at Baker one, it's true there are multiple such splashes where some champs are not focused that much as I'd expect (for example, Leona in the Baker one).
http://3.bp.blogspot.com/-fFYsgWbgiKI/U4ePjGuWfLI/AAAAAAAAQow/ftcJDmaAPE0/s1600/Karthus_Splash_4.jpg