Sealed classes - would you want them in D?

[ketmar]

H. S. Teoh wrote:

p.s. and struct with `alias this` will allow us to extend it with fields 
too. not without using some other tricks, of course, but as there is a 
documented and ligitimate way to workaround any "sealing", i myself see a 
little sense in such feature. the only thing it will be good at is annoying 
users, who will be forced to write workarounds.