As a meta comment, typically comments added to closed issues aren't tracked very well (or at all after a while). It might be better to raise a new issue as a feature request.
With respect to your suggestions...
Having an includes is a reasonable suggestion but in my experience is relatively rare. Typically the things which make up an object's external identity (and hence might typically be in equals, hashCode etc.) are its properties. Anything which is secondary in nature (typically but not always) might be a private field. So the need for excludes is rather rare - and hence the use of includes would typically be lots more work. But perhaps you have a different use case which should be discussed.
Regarding an attribute level annotation. Again another good idea but when we considered it initially, became a little bit messy. Would the annotation be @CanonicalProperty or just @Canonical, @ToString etc. in front of attributes? What it both @Immutable was in front of one property and @Canonical in front of another. Certainly a class with 20 properties soon became very non-DRY looking if each property had several annotation in front of it. Anyway, worthy of further discussion but I would suggest fleshing out some details so that discussion can progress further. Also, seeing what other people do, e.g. project Lombok helps make such arguments more persuasive.