I wouldn't call myself a standup in the presence of Jerry Seinfeld or Chris Rock, but I do my share of it and it has been and remains part of my activity and I like it.
The key to writing for Richard (Pryor) was to just push his buttons and then know when to push the buttons on your cassette recorder. You'd get him started, then surreptitiously start recording when he got inspired and started walking around the room and improvising in character. Then you'd get it all transcribed and take credit for it.
And introduce an element of cynicism and darkness into it and just realize that we're all vulnerable. We are humans. There is a finite end to this life and we're all going to face it and a little silliness can help.
If a director can find the exact combination between the written word as a guideline and improvisational input from his actors, I think that's where you'll find the most successful work being done.