I do think McInnes had went stale and I fully expected them to part ways in the summer. Very surprised by the timing. His Record is pretty outstanding.

A cup win
Never Finished below 4th place. 2nd place four times (Twice when Sevco in league), 3rd once, 4th once (currently in 4th)
4 cup finals (3 v Rodgers Celtic).
7 years in Europe in a row with 6 of those got to the 3rd Qualifying rounds (getting drawn against Maribor, Sociedad and Sporting lisbon is tough going they even got Burnley in the 2nd Qualifying round)
constant rebuilds.

I know their playing style hasn't been great and i do think they have slowly been going backwards but I don't really know what more he could have done. He has re-established them as a top 4 team competing for the cups and in Europe every season. Their next appointment is massive because if Cormack goes for the wrong man they could easily end up like ourselves or the Edinburgh clubs then will find out very quickly that the grass isnt always greener.