It is not possible to directly modify a modulator type once it has been associated with a parameter. You have to redo the entire modulation process.
Example: you’ve assigned a classic LFO to the Cutoff parameter and now find it more appropriate to use a “Segment” modulator for it.
If you need to do this, you must: delete the modulator (and lose the mapping parameter), choose another modulator and finally redo the mapping process.
What problem(s) would this feature solve?
It will improve the modulation workflow (which is Bitwig’s main feature!) by replacing 3 actions by one. Computers were built to avoid repeating the same process…
How does this feature fit into Bitwig as a product?
Add a “replace” element next to “cut” “copy” “paste” “delete” for modulators
Is there already another way of doing this in Bitwig?
Not directly. You need to perform 3 actions and, above all, try to repeat the actions you’ve just performed.
Would it be possible to implement this using Bitwig components or APIs, without the support of the Bitwig team?
No
Could it be provided by a VST or something else reasonably integrated with Bitwig?
No
Are there any other products that offer this functionality?
No, because Bitwig is the best for modulation.