I can see good and bad.
It could easily be the comfort that you both are missing. It is very easy when you are lonely to forget the bad times and just remember the good times. Especially around this time of year when family is gathering (tonight in particular!)
On the other hand - if you can look back at what went wrong with a clear eye, and both of you really take ownership for the part that each of you played in the ending of your marriage the first time - then that gives you a very realistic start for a future together. The "hindsight is 20/20" is actually a good thing, because you know what didn't work the first time.
But both of you have to be prepared to be brutally honest about yourselves in order for that to happen. Not many people can do that and live with each other. I mean, I can look back and see all the mistakes I made in my first marriage - but I don't know if I could make it work with him even then. I would always have guilt, and being with him would actually be a reminder of the mistakes that both he AND I made.