You will get 1.
You will have to pay for it.
Just like the warden.
Why don't make it 8 character slots, or 16? I think 32 might be even better...
What if you have an Altmer male AND female?
Then each of those need to have four spots for each class. Five for warden so you can have stamina and magicka healer.
Male Altmer
4x Dragon Knights
4x Templars
4x Nightblades
4x Sorcerers
5x Wardens
4x Necromancers.
=25 character slots.
The same would be for your Altmer female, that would require 50 character slots for one race. This is not taking into consideraton people that have gender neutral or fluid characters.
50 character slots per race, 10 races, 500 character slots. So we need at least 500 character slots, and that's without duplicates.
I hope that I've proved my point. Be happy if you get ONE additional character slot, and learn to prioritize.