Yep, it would be fascinating to visit the future, for sure.
As for the past, I don't know what the fascination is with visiting battles all the time. Personally, I think it would be absolutely horrific to watch real people getting hacked to pieces. The fear, the blood and the smells of any battle field would be most unpleasant to experience I am sure. I suppose the battles which have happened have happened and there is nothing we can do to change that - but going along to see it all as a spectator just seems a bit, well, ghoulish. I suppose an awful lot of human history is pretty unpleasant though. It seems to be just the way we are.
I guess I'd rather be able to go back and see more mundane things like what everyday life was like in medieval cities (probably no bed of roses, I know!). Or maybe to see how the place where I live has changed throughout the ages. I'd love to see the construction of castles, stone circles and cities. It'd be interesting to see the people carved all the intriguing Pictish symbol stones (and find out what really happened to the Picts themselves).
I'm sure there's loads of real interest in history without having to endure the brutality of battle.