I mainly have played the game for 50 hours total for the past few years because the rocket jumping is better than Team Fortress 2 rocket jumping.
Let me explain.
I once was named the god of rocket jumping in Team Fortress Classic because rocket jumping feels more fluid and more reaction based and in general it feels like rocket jumping should be. The only problem is that there is no way to resupply like in Team Fortress 2 with console commands so you have to pickup every single bag you find for health and armor to continue rocket jumping. In Team Fortress Classic when you rocket jump and hit a slope you glide up the slope and can potentially chain another rocket together for more speed.
Team Fortress 2 rocket jumping feels more like you are magnetized to the ground and more sluggish. When you try to rocket jump and hit a slope you get stuck on the slope instead of gliding up the slope. No idea the rocket speed comparison of the rockets in Team Fortress 2 compared to Team Fortress Classic.
In conclusion rocket jumping in Team Fortress classic feels like rocket jumping and is right the way it is while Team Fortress 2 rocket jumping feels more stubborn and you have to do it perfectly otherwise your just not going to go anywhere. Team Fortress Classic rocket jumping has more margin for error and is generously forgiving compared to Team Fortress 2 rocket jumping. I could never get the hang of rocket jumping in Team Fortress 2.
Final thoughts
If I could change Team Fortress 2 rocket jumping i would give the same sliding effect or whatever in Team Fortress Classic and the gold source games when you hit a slope with speed instead of having speed removed when you hit a slope at a bad angle. And finally I would try to fine tune the rocket speed for the rocket jumper to be around the same speed as the rockets in Team Fortress Classic and have the same knock back.