the bXX command isn’t affected by the delay column 
I assume this goes for others, too (volume and pitch slides), although I haven’t checked…
I know it would break/change stuff, so maybe it could go as a toggle into song properties.
If you would have 4 subcolumns in a track which have 3 delay columns filled with different values, which delay column value should be applied to the fx column?
The one that is most to the right?
Wouldn’t matter much for me, I rarely use differing delay values between tracks, it’s more a way to get some swing for me than to cram many notes into one line.
(which is why I suggested a delay column for the master track a while ago, but IIRC nobody cared about that much)