I just took the cassette off my wheel, which involved hitting it with a spanner and applying WD-40 before it would get off. Looking at the body afterwards revealed why: lots of wear.
https://drive.google.com/file/d/0BxxysHtIvGATYXA1S25GOEdmaUk/view?usp=sharing
So, hive mind: should I get a file out and smoothen this down a bit before putting the new cassette back on, or is this time to buy a new body or whatever that bit is called. It's a Hope Pro 2, so presumably I can replace the freehub without having to build a new wheel.
Deburr and carry on. That's fine. Probably would have come apart easier if you'd used a chain whip to "unwind" the loose sprockets.
Hope also recommend only using a cassette with an alu carrier.
Yeah, using the chain whip makes sense in hindsight. A XT cassette is going on, so that's alu afaik.