First, there's a bug in the F10 'Customize UI' screen. While mounted on a horse, I press F10 and decrease the font size from 35 to 20 as I've done with other status bars but the game doesn't 'remember' my new settings. Not a huge deal but mildly annoying to have to change it each time.
Anyway...as for suggestions...they are also horse related. I really think there's a missed opportunity regarding training horses. I think I should have a chance to create 'Unique' and 'Named' Warhorses at some point (90 for named and 100 for Unique) in the Warhorse Handling tree. This name should appear rather than 'Warhorse' or whatever when you're pointer is aimed at it.
Also, somewhere in there should be the ability (at Level 0) to 'Give Treat' (give your horse an apple or carrot) then later, to 'Call Mount' (your horse will come to your location when called/whistled. Obviously this would have a limited AOE, which perhaps could increase with skill...
Anyway, first post so I won't go on...but got the game about a month ago (already at 450 hours lol) and must say...I absolutely love it!!