With my only timing experience being GH customs, I found timing in the osu! editor a lot harder compared to the GH chart editor Feedback. The one feature i found missing in particular were anchors. Anchors are a little hard to explain, but think of it as this:
You go to a certain point in the track and put an anchor there, which you can use to specify that at that point you want it to sync up with the song at a specific time. You then put another anchor elsewhere, specifying another time. The program will then automatically calculate the BPM that is needed to make the space between those two points last the time that you want to be between them.
I've found this to be a very useful solution to time songs with variable BPM, since you can easily move a note forward or backward a little, listen to it, and put an anchor on the place where it should be to have it sync up. I can't think of the best way to implement this in osu!, since both systems work quite differently. In osu!, you can place a timing section on any given time while in GH you can only change the BPM, which means you can only place a timing section where you can place a note, making tools like this more important.
To give an example of it's usefulness, while struggling with the timing on this beatmap I thought of doing it the Feedback way. While my accuracy with my old timing was worse than you could imagine, after transferring the BPM changes into osu!, I nearly SS'd all the sections I had timed in Feedback on my first try (100s were mostly my own fault I think).
tl;dr: Anchors will allow you to time EVERY song perfectly without having to have some sort of BPM sensing abilities.
You go to a certain point in the track and put an anchor there, which you can use to specify that at that point you want it to sync up with the song at a specific time. You then put another anchor elsewhere, specifying another time. The program will then automatically calculate the BPM that is needed to make the space between those two points last the time that you want to be between them.
I've found this to be a very useful solution to time songs with variable BPM, since you can easily move a note forward or backward a little, listen to it, and put an anchor on the place where it should be to have it sync up. I can't think of the best way to implement this in osu!, since both systems work quite differently. In osu!, you can place a timing section on any given time while in GH you can only change the BPM, which means you can only place a timing section where you can place a note, making tools like this more important.
To give an example of it's usefulness, while struggling with the timing on this beatmap I thought of doing it the Feedback way. While my accuracy with my old timing was worse than you could imagine, after transferring the BPM changes into osu!, I nearly SS'd all the sections I had timed in Feedback on my first try (100s were mostly my own fault I think).
tl;dr: Anchors will allow you to time EVERY song perfectly without having to have some sort of BPM sensing abilities.