It depends on what we want. If we want to get up this season, and not think about the future, then I think we should seriously consider Neil Warnock - as much as I dislike him. Look at what he has done at Cardiff ever since he was appointed. 39 matches, W18 D9 L12, 1.62 points per game. With a Cardiff side.
Previous to that, he somehow managed to keep up Rotherham in the Championship thanks to an unbeaten run of 11 games. 16 matches, W6 D6 L4, beating the likes of Middlesbrough, Sheffield Wednesday and Brentford. No surprise that when he left, Rotherham were a complete and utter failure and finished bottom of the league.
My point is, he has a bad reputation, he's not a very nice person and it would be a pretty ugly appointment. But, he's a damn effective manager and I think this squad would suit his style of football perfectly.