I have one TB and 8 shetlands wouldnt change too much but this is what i would change.
That my TB didnt like to roll so much in the worst of the mud.
One shettie would grow up and stop trying to jump on me while cleaning stable (am working on this with not much progress).
And that I had registered papers for another shettie cause he is amazing but I rescued him and cant find out his parentage, even though he must have been registered cause he went through shetland sales.
All others are perfect in every way and wouldnt change them one bit.
Storm - wouldnt change a thing about her she is fab but a new front leg would be nice so we didnt have all the lameness issues
Cloud - 20 yrs younger although he already thinks he is 4 !
I'd make mine less of a loony tune so I could have a day off from riding her atleast twice a week and she would be happy with just a day in the field.
I'd like to find the little thoroughbred a lovely hunting home