I am hyped for the league however all the "get x level" sound very boring. Having tasks that require using these skills would be much better.
I hope this league will be successful and jagex will put more development into next one.
It just makes sense to have tasks that reward people for skilling, it's a big part of the game. There are plenty of tasks related to specific activities in-game such as aerial fishing, wintertodt, tithe farm, raids, achievement diarys etc. which are using the skills like you said.
As well as other simpler diary-esque tasks