I thought patterns are just meta/group packages. Do they do anything else differently?
It's been a while, but I remember patterns trying to re-install things that I removed and I didn't like the work-arounds listed. I can't remember what exactly it was, but I don't think it was anything I really needed even with whatever other thing it was grouped with.
Doing a search and it seems other people have been annoyed by patterns because of "recommended" packages, I don't know if it changed though.
what issues do you have updating them?
Some of it is the internet again (especially pulling down things from git that are quite large), some of it is stuff that just fails during building. Basically I can do a system update just fine, but I can't really expect the AUR update to go smoothly. I just pick-and-choose what of the AUR I try to update most of the time, luckily things often just continue working.
are the no-longer-available packages orphans?
That's an issue too, but no in this case I mean packages that have most likely changed names (or maybe removed) so replacements must be manually found. Unless there's some tool I'm unaware of. Otherwise, they will just never be updated, which is often fine. A lot of them are libraries that I'm not even sure about.