adding more methods for interp and interp2D by flags

interp calculates a value using a linear interpolation, interp2D uses a bilinear interpolation (this information is missing in the manual under displayhelptopic "interp2D" and can only be found under displayhelptopic "interpolation").
There are functions with interpolate2 and ImageInterpolate that allow other methods for interpolation (spline etc.). However, these functions do not return a single value, but create a wave with all possible interpolations.
My wish would be that interp and interp2D are extended by the other methods of interpolation. The wanted method could be called via a flag.

First note that both Interp() and Interp2d() are functions and as such they do not support flags.  The only way to implement support for optional interpolation methods would be by adding optional function argument as in:

Interp2D (srcWaveName,  xValue, yValue [,method])

Please send your suggestion to and include listing of specific methods that you want to see supported in each case.