I think a key thing that hasn’t been mentioned is that the gear you are using dictates to an extent where on the improv scale you can practically be operating. My 4 voice multitimbral PreenFM2 is a nightmare to even consider sound designing with on the fly without extensive setup. Do I still use it when ‘improvising’? Absolutely!
I prepare a ‘combo’ of four patches combined together into a set which I assign via midi CCs to a pattern in my Digitakt live techno project. I set up the four ‘performance’ macros as my E-H encoders on the DT, and have them routed to the ‘Index of Modulation’ values of whatever patch they are pointing at, allowing me a wide range of sound options on the fly. So I have a fixed starting point with those voices, and a range of which to select (it’s only practical to use one or two voices on the fly) but it certainly allows me to go in unexpected directions.
My Quadrantid Swarm is far closer to what I think of when I think of an improvised voice in techno, where I can move the pots quickly into a starting point and then use the whole instrument to go wherever I fancy. But really, is there any difference between me knowing a decent starting point and quickly twisting a few pots and doing a few patches to get there compared to loading a starting point combo on the Preen?
On my DT, my live template has a bunch of patterns with most of the tracks already populated with sounds, but with only one or two basic sequences, usually a kick plus one other element, so I have something to switch to when I want to transition. Obviously I don’t want to move to silence in a progression, and I don’t currently use a looper, so ideally I want something to be there when I get there, and a four on the floor kick, or a simple variation, gives a starting point to quickly sequence away from.
I guess the question is one of established (or in this case unestablished) idiom. If you are interested in this area, I recommend Derek Bailey’s book called Improvisation in which he has conversations with various professional musicians from various disparate fields about how improvisation functions within the traditions and idiom which they are a part of. This includes Baroque music, Indian classical music, prog, Jazz, modern composition, etc. I play the recorder family of instruments, mostly for early music - Baroque, and I am called on to improvise whenever I play a Handel or Telemann sonata! But what improvising means in that context is very different to what a sitar player would consider improvisation in a free section of a Raga.
I think it’s both important to note that:
if you specify that something is an improvisation and then do a ‘performance’ of a mostly pre sequenced song with a few modulation changes and some on the fly variation, you should expect push back from people who do differently, and take a more strict view of what improvisation entails, and;
if you fully improvise, you can expect to be met with bewilderment by the majority of the electronic music audience with expectations aligned to what they hear commercially released.
I don’t care either way, but I think it’s perfectly possible to say in a few words what you are doing when you post a video or audio recording, and I think the outcome is best evaluated in this context.