Menachem"The rocket launcher needs to allow for soldier to deal damage and be mobile at the same time, without making him too hard to kill."
This is only tangentally related but I think it's important to not overstate Valve's original intent of balance as it relates to modern 6v6 metagame, and rocket jumping is like a microcosm of that. If you look at early TF2 videos of how rocket jumping is presented, it seems pretty obvious to me that Valve never intended for rocket jumping to be as mobile and advanced as it is now.
If I remember correctly from either in game commentary or Valve talking about it early on, the Uber was basically designed to kill sentry nests. Heavy is obviously the intended med/uber target in their original design of the game, I don't think we need to take what they "meant" the game to be into consideration.
I guess you can tie that into the discussion of whether you should nerf the IB or buff GL, in that what Valve intended for the power level of the demoman to be in the game as a whole doesn't really have THAT much bearing on how we want the balance to look in our game.
Also there's some weird Death Of The Author argument in here