Thanks for sharing this suggestion. We've actually wanted this ourselves for years, since we also use large trace outputs ourselves, and having the ability to colourise them would be really nice.

We made several attempts at it, but discovered it was actually much harder than we expected it to be due to the levels of optimisation around the text control used to show the trace output. We have an additional constraint that Rider and VS don't: We need to be able to perform a full refresh of the visible trace output without utilising the UI thread for more than 20ms on mid-range hardware. This is because under NCrunch, the tests are re-run while you're working in code, so having the window update itself in an expensive way can have a noticeable impact on the 'drag' inside the IDE.

Difficult is not the same as impossible, and there are potential solutions to this problem, but they require a lot of work, which makes it unlikely that we'll be implementing this.