I think you need to separate what people want to play as opposed to answering real question, which is what race is most fitting.
To me it's a no brainer. Based on location, trailers, lore, etc. it has to be a Nord. But I can tell that some people are answering instead what they want to play instead of really answering the question. Honestly, why would some of those other races be more fitting? Back that up with something other than your desire to play that race, noted that some have already done this.
Being Dragonborn has nothing whatsoever to do with race or bloodline; the Septim Dynasty was very much the oddball, and was the result of a pact between Tiber Septim and the Aedra, to stand as guardian of the Dragonfire spells that kept the dimensional doors to Oblivion sealed. That is the only reason the Septims were born one Dragonborn after the other. And it is not a matter of simply being born with the potential. There has to be awareness of what you are, and training to even begin to wield the power. And for quite a few centuries, that power was blocked by whatever sealed the dragons away. You could maybe learn some shouts, but without the souls to power it, the effects were probably minimal, if any. Yes, the Nord's had Thu'um.....or more accurately, they learned to copy a tiny bit of the Dragon magic (You'll notice that -none- of the recent Septims seem to have given a shout....even when it would have been to their benefit. Such things go into history, after all.....).
Skyrim is in the midst of a civil war. A nordic Dovakhin could easily be drawn into it......and thereby screw up and cost the world its life. Someone who isn't so emmeshed with local events might be better.
Someone who knows loss would be a better choice than someone who has never seen blood or death.
Dragonshouts are magic; wouldn't one of the magical races be better equipped to handle or learn them?
Sure, I like to play my Dunmer lass.....getting into non human opposite genderthink is challenging in its own right. And as circumstances are set up, with so many refugees from Morrowind, you could have 'Dunmer' who have been born and raised in Skyrim....and don't really consider themselves either race. And hence might just avoid the foibles of each, and find their own problems to trip them up.
And besides, if you gotta choice, then you ain't gotta do 'the obvious', do you?