His Serenity, the Doge, elected by the whole populace? Term-limited? A bit like the POTUS then?

Personally I'd keep the Saxe-Coburg und Gotha chaps in their gilded manacles; if they still want to do it that is. The option between Charlie and the Donald falls squarely in Charlie's favour. Just think, Australia could get Pauline or similar as their Prez... Well maybe you'd be sane enough to elect someone sensible, but it's a strange old world. I always think that if it ain't broke, don't fix it. That way evolution happens, not revolution, as the broken bits get dealt with, and the rest carries on, providing continuity. It does mean that reform becomes a sort of continuous firefighting operation, but it also means that unnecessary reform isn't done for reasons of ideology or symbolism.

There is no point in changing things to put something worse in their place.

Edit.
As I may have mentioned before, I am a specific kind of conservative, but one nevertheless.