I think that they don't make tables of 2 or 4 because at the real beer houses in Germany, you are seated at long communal tables, and they were probably going for the "real experience." JMHO. I would like to sit by ourselves too, but I will gladly sit with another family just for the band and the yummy food.
We were there in January and had a wonderful family sit by us. At first it was a little wierd, but after a beer WHO CARES?! LOL!! We ended up taking pictures and dancing with them and were so sad to have to leave. I think we were there for over 2 hours!
It was one of my favorite experiences of the whole trip, but you get out what you put in, if that makes sense.