The playing personal is one topic (personally think having Burrow and Delaney not fit/fully fit at the start of the year helped with picking Aiton and Ward, likewise when Sinfield went down and Sutcliffe came in.
The other is how we are playing in terms of style and adventure. We went to Saints last year when they had more injuries than this year (and we were pretty much full strength) and we dominated a lot of the game yet just tried to barge over the line in repeated lack of ideas style (or cautious didn't want to play risky error filled style) and ended up losing because we couldn't score enough points even though we spent enough time down near the opposition tryline (a reoccurring theme throughout 2014).....12 months on, similar squad and we look like the most risk taking, adventurous, entertaining side in the competition.
Coaches throughout their careers will have varying success......but throughout even if they change clubs with different personnal you can still see their teams play a similar style under the coach in question. It's extremely rare to see a coach oversee such a varying style of play from a team they're in charge of, especially just several months apart with so few squad changes made.
If you'd have watched our performances in 2013 and 2014, then watched what we've done in 2015 so far WITHOUT ever knowing who the coach was in that period, you'd probably guess that they'd been a coaching change before the start of 2015.