Taper-free bezier curves etc.

Currently the only bezier curves Musescore can draw are for slurs and ties and get the default thickness tapering that applies for the whole score.
But there are many examples where it's useful to draw bezier curves without such tapering, e.g. to indicate inexact but smooth changes/bends in pitch (e.g. harp glissandi, or even for instruments like the theremin). See https://musescore.org/en/node/316889.
Adding such a feature would be reasonably straightforward as it can be done already by using slurs (anchored to invisible notes) and setting the score-wide end and middle thickness for slurs to the same value (but unfortunately can't be applied to just individual slurs).
A secondary arguably more powerful feature would be "chained" bezier curves with matching gradients that would allow simulating almost any type of curve (including sine waves and the like). However that probably needs more thought (whether they're still individual but connected elements, or the whole chain is a single element with an arbitrary number of inflection points).
Note I don't understand the suggestion that these should be drawn in other tools and imported somehow - how would part extraction work in such cases, let alone copy/paste where in some cases the curves may need to break over systems or be adjusted according to the spacing in various parts of the score? The pitches may be inexact, but the timing in the measure isn't arbitrary - if I draw a curve that's intended to inflect on the 4th beat, then I'd want it to be shown like that regardless of the spacing, which might be very different depending on what's going on in other parts.