I love Deboer. I loved him in 2011-2012 (obviously), loved him last year, and love him this year. If the Devils kept playing like they did earlier in the season, I always said it had to be Lou gone before Pete. The effort is there 97% of the time with this team. The system works well for the personnel, and they generally out-chance the other team.
I think a real sign of a good coach is how the team responds when things aren't going there way. It's very easy to coach when you win games and get good goaltending. But that hasn't been the case for the Devils over the last two seasons, and that's been damn impressive. No one feeling bad for themselves. Everyone fighting hard until the end. No leadership concerns or issues. No lockerroom chatter. He doesn't call anyone out publically, and I like that. This is a team that lost 10+ games in a row, and it was business as usual (and that was calm, professional, and playing pretty solid hockey all things considering).
There are issues I have disliked, but only personnel ones (goaltending, Fayne/Harrold/Larson, Gionta, Janssen Josefson, but these are all relatively minor for the most part. The goaltending one is probably not, but that's about it.
I doubt Deboer was ever close to being canned, but he would have been hired by another team in minutes (not to go all Rob Ryan on everyone). He's well respected around the league, and most people would put the blame on all the personnel the Devils lost and didn't replace over the last few years as the reason and rightfully so.
I don't see many coaches doing a better job with the roster over the past two years than Pete.