It would be nice to be able to select just one column of the effect parameters. that way, we could transpose or interpolate one parameter. effects like 4xy vibrato, the x and y affect different things, yet the interpolate and transpose functions treat them as if they were one value [xx].
I think this could be handled just be being context sensitive on this, i.e. if you happen to be interpolating 4XY, it should automatically interpolate X and Y separately, but ZXX should interpolate them as a single 2-digit number.
(I suppose if your interpolation range has different effects in it, it could just switch modes whenever it hits a new effect. Not really an important case though since interpolating across effect types makes no sense anyway.)
Just wondering, do you ever use interpolate on 4xy? The one case I can imagine is interpolating the depth value, but that should work fine already since it's the first digit only.