I think the swivels make for a good seat height. Never really thought about it before, but it does seem high, although actual driving, looking out the windows and for comfort I think they are great.
I'd probably feel weird in a van without them now... although I recently drove an 07 with no interior and didn't even notice. It didn't even have sun visors or a rearview mirror so if it was drasticlly shorter I would think that the perception would have been increased, but as it was I didn't notice the seat hight difference.
I've sat in later models Wranglers where the seat is ~3" shorter and I can't stand it.
I'm 6' too. HTH.