Anyone see the finale? It thought they could have done better, I was a bit disappointed. At least he and Rose didn't Marry and I assume he got back together with his other girlfriend. Hopefully he was the baby's father. Why was Mary not with the family? Does Jessica Biel have something against the cast or was the episode written that way?

Yes, it could have been better, if it had been a two-hour finale or a two-parter.
But for the time allotted, it was about as good as could be expected. It was
kind of fun seeing the flashbacks of the younger versions of the Camdens, and
the way in which the "alternate endings" to the wedding were presented was a
novel concept. With both Simon and Rose having doubts, I was pretty sure the
wedding would never take place. I wasn't sure who would stop it, but as it
turned out, Simon and Rose never even let it start. Wasn't the fact that
Martin was the father of Sandy's baby established in an earlier episode?
Re Jessica Biel: it might be that, due to her schedule, she was unable to
film her scenes with the entire cast.

Well remember, Sandy didn't want to make any trouble for Simon and she did sleep with Martin, so she thought he was the father. The flashbacks were the best part of the show.