I use standard for spinners, another variable, cause I dislike the spinning mechanic on classic.It is complex indeed. I've generally tried to keep things as "basic" as possible, using mostly default. I've only adjusted some batting sliders because I found medium too easy but was getting slaughtered (like under 50 and not able to play an attacking shot without edging) on hard.
I do use bowling hud, but i try not to look at it for seamers, i do need it for spinners though.
I play on a modified Hard for batting I think, likewise I find Medium too easy.
I'll throw the idea out for mods/BA to decide if it'd help but maybe threads to feedback specifically about each difficulty would help. No slider adjustments just everyone play on Medium/Classic for a week and at the end of the week feedback on how it feels. Oh, everyone agrees that slogging is too hard, let's try this setting instead and see what the consensus is. Then next week we try hard. It's admirable to allow the individual adjustments but I always tried to play on default until I had to change cause I think the out of the box experience should be as good as possible. The first thing you think about when getting the game shouldn't be 'what's the best way to change it?'
You could narrow down which aren't used and just remove them. Honestly think you could lose the bottom two difficulties and no one would be bothered even without that.