Lots of divers will tell you that buouancy control is difficult for most divers. Mine is absolutely good. I teach underwater photography and can hover within a fraction of an inch over a super silty bottom while swimming backwards and taking video without stirring up anything.
I have other instructors and professionals come to me for buoyancy training.
Lots of diver don't know their buouancy sucks because they overweight themselves and stay neutral by having poor trim. They angle their feet downward and kick to stay neutral, which uses more air and causes them to silt out the dive site because they're disturbing the water below and behind them, but never see it because they're not facing that direction.
Most of my photography classes are actually teaching buouancy and advanced kicking because you really can't do good macro shots from 8 feet away. You have to get to the subject of the shot, and have to be able to do it without stirring up the silt.
The frog kick, back kick, and helicopter turns are essential skills, but a lot of people have shitty or gimmicky fins, which makes it much harder. My thought on fins is that there's 2 kinds - Jet Fins and Bad Fins. They were designed in the 60s and have never been matched.
Those big, heavy, stiff monsters are great, because you can do a reverse frog kick without them bending and pushing you forward while you're getting them in position for the back kick.