For me, comparing start of the season to the end, most improved was Sembie-Ferris.
Most regressed was Cam Wilson, for the first month of the season he looked good on the left side of the front 3. Did well against Tamworth away, seemed to be making chances in games, won a pen against Peterborough that Whitehall missed and scored that great goal against Scarborough. Somehow he disappeared to be a bit part player and ended up getting loaned to Scarborough (where I believe he did ok again).