Thank you - but you seem to be missing my point that in your post which I quoted above, you state that "Users at trust level 1 can... use all core Discourse functions". That includes "Reply as New Topic", and therefore implies that is a core Discourse feature. And, as I said before, users at TL1 and above should surely not have their access to features restricted on the basis of physical ability or otherwise.
It also doesn't answer my main question as to whether keyboard shortcuts not working or other items inaccessible by keyboard should be reported as bugs or as feature requests.
If a shortcut listed on the shortcut menu doesn't work, then that, to me, is a bug.
If something else doesn't work when accessed by keyboard, that, to me, is also a bug.
If I'm going to take the trouble to list them all here, having already listed them once on our sandbox, then I would at least like to know I'm posting them in the right place for them to get attention.