Basically Mills played ultra-Swansea 2012 football, passing the shit out of it and keeping it on the deck. It was good enough to get us to the play-offs. Aspin on the other hand is the complete opposite, ultra hoof ball with little to no real alternative. It's absolutely turgid to watch and has ultimately cost Gateshead a few hundred fans each game.
Not sure we'd be able to convince Mills to come back, but I'd definitely be going for someone who has a track record of being able to balance attractive / effective football. People are calling for Richard Money (remember him?) who has a very good record at this level and won League 2 with Wallsall in 2007.