The lore behind why the Falmer are as they are now is actually pretty good and explains quite well why they what they are.
yh. I go with that. I think the devs made it this way to explain their absence as a playable race. I think the lore to them is pretty cool. They were normal elves who became hostile creatures due to thousands of years living deep underground without day light.
A similar race to the falmer I'd also like to see if they ever make an Elder Scrolls game set on Summerset Isle is the Maormer who are sea elves / tropical elves who live on tropical island of Pyandonea (SE of Summerset isle). I'm expecting them to be kinda based on the Maori / Polynesian people who live the tropical islands of Oceania / Polynesian in the Pacific Ocean which'll be cool to see an Elven people like this.
http://i.telegraph.co.uk/multimedia/archive/01737/maori_1737085c.jpg
This time I'm hoping they remain a normal race though.