if the scrolling is like in taiko you can not make alot of bpm effects(tricks like in festival of ghost 2 like in the video are not possible then anymore). also it would be very weird on SV changes because the notes that are changed will come faster than the notes before it so notes are falling each in different speed.You can't even make bpm effects in most songs unless you double or half the bpm.
No. There will not be a time when 2 notes will fall at a different speed.
the way it is now is better i think because it feels like the notes are lying on the field and the field is moving towards you with all notes at the right place. If you change that to taiko like scrolling it is like the field stops and SV controlls the note speed. It is very inaccurate and looks bugged on speed changes.???
Also if you let the mapper chose the scrolling speed is just stupid again. Everyone should set it before playing to their speed they can read and are comfortable to play. also this will probably lead to abuse by the mapper and dont say now somethink like "mods can take care of that" because it is not going to happen because everyone got their own way of playing and what works for one will not work for the others most of the time. also it is inconsistent because you will end with different speeds for songs with same or close BPM which is stupid again because you have to remember what speed to set for each song seperately.Changing scrolling speed within a map emphasizes some parts of the song. And I don't think abused maps would be ranked anyways, unless the diff is uber insane.
??? This will be a multiplier, and it will not change your map speed preference.
I have played a different fan game like osu mania before and it used just that taiko like scrolling that you want and it was really bad. It was just annoying to play the inconsistency in speed modifiers and you could do none of the BPM tricks you can do now. I dont know know what tricks or creative stuff if you have in mind but just try in osu editor doing some of that in taiko mode and see if that works for you. Or if you want i can link you the other game (it has an editor aswell and basicly is what you want) and try there first and see if your going to be happy how it is. For me the way it is now it is like the original and its the best, and i hope those SV changes never get implemented.I don't really know of any bpm effects you could add in a song with a constant bpm. And if you think that notes would fall at different speeds at the same time, you're wrong.
Sorry if I'm not getting your point that much.