Some dads are going to be worst than others, regardless, but going on a course together like a hypnobirthing one for example, can help a lot - an educated dad is probably much more use than a clueless one.
Also there's the fact that, particularly in hospital, the dad can feel like a bit of a spare part, he's an alien environment and surrounded by people who apparently know much more than him, doing strange things to his woman.
I had a homebirth for my second, and that really brought home to me how much better it can be for dads at home - he was kept busy almost the whole time - clearing the room, setting up and filling the birth pool, putting music on for me, getting me water, giving the massage we'd practised beforehand. Then dealing with my dd1, getting her up, getting her breakfast. Then the midwife - getting her coffe and toast. And when he didn't have anything to "do", he was in his own home - so he could do whatever he would normally do - eat his own breakfast, read, surf.
I didn't really need his support as such for much of either birth, so in hospital found it slightly annoying to have him sat there for long periods of time staring into space or reading, obviously rather bored. At home there was so much more for him to do.
I do think it would be not have been very nice for him to have missed either birth though, I feel it was important (for me) for him to have been there, as having children is a team effort for us. Not sure if he feels as strongly about it though.