The only change I made to the pattern was to attach the leg bands like a binding that wrapped around the leg holes rather than the flip and top-stitch method used on the waistband. To me this made them look more like undies and less like training pants.
My son somewhat logically couldn't fathom the purpose of a y-front for his 4 year old self, so a couple of his pairs have a non functioning front piece.
After a friend saw the first pair I made, she asked if I could make some for her son too. He had very definite colour and pattern preferences, so the finished collection had a bit of a multi-pack look to it.
I really recommend this pattern, and will definitely be making more of them with my younger son about to start toilet training.