Snail shell - that hits the mark. It’s enough to drive you crazy. The stairwell wall as a reception committee is more off-putting than welcoming. Sorry, but the whole thing would go straight into file P for me after a quick skim. That’s why I’m wondering if you want to keep fiddling with it and whether we really have to list all the weak points?
By the way, I can stop you worrying about the vestibule and cold feet. You don't see that in new buildings anymore and it’s completely unnecessary. Basically, these days you can easily put the front door right into the living room – everything is sealed and warm. The energy saving regulations have to have some advantage after all.