Okay I gotta be honest, calling wall-bugging a skill based mechanic is a big stretch. Half the skill of it is simply knowing where the bug can be used. Speedshotting requires impeccable timing with your rocket to pull off, along with Ctapping. Both give advantages while legitimately being harder to do and requiring a degree skill and there is progression to how good you can get with each mechanic.
You can literally teach anyone who has really basic rocketjumping ability how to do a wall-bug, you just need to know where to do it. It's not skillful nor is it a movement mechanic that adds layers of depth to the class. Floating on invisible walls is also not even close to the same thing as hiding on a physical prop because there is absolutely zero physical indicator you could be there or should be there.
It just adds nothing to the game but a tool for people to get easy forces or kills in a manner that is not conducive to competitive play simply because of how random it is. Which walls are we supposed to check? Are we supposed to go into a map editor to find where these spots exist or just kinda aimlessly jump against them until we find one? Again "hiding spots" are different because there is a visual indicator that someone could be there, and it makes logical sense in the game world. (edit: I was corrected a bit on the nature of finding these spots but I do think this is still overall applicable)
Now personally I don't think it would've had much of an impact on the OVERALL result of our match against you since you guys were the better team (it definitely affected a push or two though), but going forward I don't think it should be allowed personally.
Also as a side-note it's really egregious to say that somehow it's no big deal because in actuality the floating soldier is really easy to kill. That's simply not true, any invite team with sense would simply pounce on that scout wasting time shooting the floating soldier and kill him and get the force. You see teams like Froyo do this all the time even when there isn't a soldier floating in the sky. The scout is taking time to clear traps for his team? Jump on his head and kill him. The push is now stuffed.