I think that the fact there is no level cap in general is slightly absurd to me, but I have come to terms with the fact that this will most likely never change. With that being said, I think there should be a level cap implemented on every rank below SoaF III. For example, Heebie Jeebies I would cap at level 3, then II would cap at 4, and III would cap at 5. Same thing for Horrors I which would cap at level 6, then II at 7, then III at 8. Primals I at level 10, II at 11, III at 12. Doomsday I at 14, II at 15, and III at 16. Finally, SoaF I would cap at 18 and II would cap at 20, and SoaF III would have no cap.
I feel like this is personally not too much of a problem with me, as most of my Phobies range in the 18-21s, but when I am watching my friends play I notice that sometimes it seems substantially unfair. I also find players I have been queued up against to have Phobies of a severely lower level than me sometimes, causing them to surrender almost immediately. If a cap was instilled in games, and for players in differing leagues, on the player of the lower league (this is regarding arena, as async doesn’t suffer from this as much) it would make games for both parties more enjoyable. This change would still reward players that have higher level Phobies, but not make the game feel incredibly one sided.