Your class gets extra abilities as you level up. Why shouldn't your race (and your background) get extra abilities as you level up as well?
Nothing too drastic, maybe an extra tool or language at Tier 1 (you can pick any, but you are encouraged to pick ones that fit your race/class/background), and a free Racial Feat at Tier 2, and expanded background bonuses at Tier 3, maybe an extra skill and a stronger Background Feature (Nobles get lands, Criminals get criminal minions, etc). Something for Tier 4 too, for the few who ever reach it.
Nothing too drastic, maybe an extra tool or language at Tier 1 (you can pick any, but you are encouraged to pick ones that fit your race/class/background), and a free Racial Feat at Tier 2, and expanded background bonuses at Tier 3, maybe an extra skill and a stronger Background Feature (Nobles get lands, Criminals get criminal minions, etc). Something for Tier 4 too, for the few who ever reach it.