PS: So to provide a new electric instrument even nowadays not only a
computer and a keyboard is needed. The virtual instrument might work on
some distros and on other distros it might not work. It might work with
some computers and sound cards and MIDI interfaces, but not work with
other hardware. If somebody want's to provide the complete solution it's
not just having a computer and keyboard. Even when a software developer
just cares for the studio in the box and maintains it for several
releases of just one distro, but does not care about using it with
external gear, some algorithm (user friendly or not) might need much
computer resources, could cause unwanted latency etc. pp. In the end
building a synth by a circuit layout and some semiconductor could be
easier to do, than to provide software with the guarantee that the
software will do what it should do, since a wrong MIDI interface already
could cause ground loops, assumed somebody want's to connect the virtual
synth with what external gear ever.
Making new sounds for a synth always needs a learning curve. A good GUI
isn't the solution, if a user e.g. doesn't understand how a filter does
work, the best GUI for a filter can't help. What ever synthesis is used,
there is the need to have knowledge, no new synthesis will be a solution
for this "issue". The only way are "workarounds" such as the vector
control, or anything comparable to it.
Computers can't solve higher-ranking issues caused by nature.