I only know about playing games and can tell you that the main frustration (for me) in platform games is the actual jumping and landing itself.
Split second/sprite accurate joystick control is a complete no go.
Let's have our hero being capable of a good hearty jump, like Turrican, and not like some of the awfully controlled PD games of yesteryear. eg. Broderick, Mr Brick and Crazy Sue.
Standing on thin air at the side of a platform is off putting also.
Infact there were plenty of commercial games with the same problem.
The key is to produce a game that doesn't rely on your lives depending on the actual timing of the jumps.
That's what we had to put up with in the Manic Miner days; albeit the 8bit guys had a lot less to play with.
Just my thoughts.