I'm really happy overall about the changes to closing. I think the new close reasons are much less full of jargon than the old reasons.
In practice, however, I'm seeing an actual issue with one specific close reason: The custom off topic close reason.
The specific issue I'm seeing is that users are using a custom version of that close reason to close questions that should really never be closed for the reason they're giving. For example, in this question, three members of the community came up with the following custom off-topic reason:
Other: This question appears to be off-topic because it is about something that is to be read in a beginner's guide
I have a few issues with this close reason:
There's no evidence given to support the claim made; the 'stock' off topic reasons all provide clear evidence as to why something is off topic, and action to take.
It allows five people to close for whatever reason they feel like, so long as they can get 4 other people to listen to them. It provides an close reason that is not only going to be inconsistent, but has the potential to turn new users off because 'our rules keep changing'.
Grammatically speaking, it doesn't flow.
We have well defined reasons to close, we should use those. We have well defined reasons to vote down a question, we should use those too.
In this case, I believe this question should be downvoted, but not closed. In the general sense, allowing a custom-end-user-filled-in close reason is dangerous, has the potential to splinter the community, and to turn off new people from asking their questions here.
If you agree (or especially if you disagree), please let me know why. Consider this a discussion about this issue and a feature request to have it removed (based on community consensus, of course).