I'm with you on 'declarative' but I'm always sceptical about 'semantic'. Its meaning is vague, its benefits somewhat ethereal and its actual existence in the real world a matter of rumour and speculation.

If you can pin down your definition then I'd be able to provide a more concrete opinion.

> The notion of separation between information, presentation and behavior couldn't be any more fundamental.

Fundamental to whom? Outside of web development this separation was never fundamental - see the post above regarding "separation of concerns" - which is a much better candidate for a "fundamental principle"