Stick with your first thought. I like the central idea. It also makes it more inviting for guests to get up and have a boogie

I was Originally thinking about having the dancefloor in the middle of the room and the tables around it for the wedding breakfast. Thought it would be nice for the older people who don't want to dance. They can sit down but still be in the vibe and not distant.
I am now thinking would it be better to have the dance floor to the side. Any advice?

Dancefloor in the centre is great, but also remember that people will be spread out around the venue rather than grouped together which may give them less opportunity to mingle with each other.

I went to a wedding with all the tables around the dancefloor, and like swordfish mentioned, it didn't really work with people mixing. They were all next door in the bar and nobody was in the reception hall.