Most of my work over the last three years has been performing live, improv, with a drum machine (Digitakt - and occasionally Circuit).
I usually go in with only a selection of ~100 samples loaded from the drive into the project - but not yet assigned to parts, and with no patterns coded. I do it all on the fly, live. This does mean that everything tends to start off simple, and then build … but that also allows the other musicians to key off the basic rhythmic pulse and figure I’m going to use.
I generally use a combination of live step editing and live recording (from pads or keys) into the sequencer. I often use both even on a single part. Known and understanding a lot of different canonical patterns is key - so you can call them as you need - or deviate from them as desired. I’m fond of finding sites with large amounts of a style’s beats explained, and I recreate them for practice… this way I get them into my fingers.
I used to use Ableton in my live set up … but I found that it got in the way: The screen was in the way of me looking at other musicians and the audience. The mouse and keys got in my way (and I’d end up neglecting the pattern for too many bars). The constant selecting of tracks or returns to get at the effects got in the way of just making the change… For a period of time I put the computer below my table, and use MIDI controllers to map everything I needed. This was better. Then I ditched Ableton on stage altogether (still love it in the studio).
To me, the key is not getting so sucked into the machines that I’m not there with the music, and with the other musicians.