Highlights from this TGR preview:
Any of the three singers can sing anything they want at any given time - it’s not necessary to pick a particular vocal track and stick with it. The vocal meter fills as long as you are singing one of the correct vocal lines. In practice this means that all three singers will sing the verses together, and branch off for harmony during the chorus - sort of like how The Beatles did it.
I get it, but what if the two harmony singers are singing the same line? I realize that points are deducted, but it seems like it will be very hard to get everyone to sing one line since you can switch in and out.
The second biggest mechanical change concerns drum solos. Now, instead of giving players a free-form fill, the game highlights a measure containing defined notes ending in a green. Hit them all perfectly, and the measure-ending green activates overdrive.