Rocket launcher takes is easy to use only the first 50 meters. After that, you have to measure the dropoff and travel time, which does actually take a decent amount of skill.
If you get killed by a rocket launcher, it's one of these scenarios:
1.You were nearby, and he would have killed you with most other weapons just as efficiently
2. You were literally standing still for several seconds. (You have to measure dropoff for this one)
3. You were trying to avoid the rocket, but he hit you regardless. (You have to measure both the dropoff and the travel time)
The rocket launcher is a high-risk high-reward weapon, and it's perfectly balanced in it's current shape.
tl;dr: rocket launcher is easy to use only up close, after that it becomes a 17th century mortar