I agree with this. A linear progressions means we would spent more time at lower epic levels, because it takes longer to complete the quests. Maybe:
21: 500
22: 600 (1100)
23: 700 (1800)
24: 800 (2600)
25: 900 (3500)
26: 900 (4400)
27: 900 (5300)
28: 900 (6200)
29: 900 (7100)
30: 900 (8000)
Or skip to linear at 1000 which means, lvl 30 would be 8500 XP.
EDIT: I also really like the idea to spread the fate points over the epic levels that currently lack.