Yes and no, [MENTION=63508]Minigiant[/MENTION]. "Yes," that's the basic idea, but "No" in that Gom couldn't really be Epic until much later, so it would make more sense to compare him as a 21+ level character when he could have taken one of three different paths:
1) Stay as an "Adventurer" style character.
2) Add a Paragon Path (at 11th or later).
3) Add an Epic Destiny (at 21st or later).
A side question would be whether an Epic Destiny requires a Paragon Path, but I don't think that's very important at this stage of the game.
I would imagine that an Adventurer (or Core) character would slow advancement after 10th level, something like in AD&D when HP went from a hit die to +1 to +4, depending upon class, and with minimal increases in other stats (defenses, AC, attack, skills).
A Paragon Path would not only add unique powers - say, a new "Paragon Talent" each level - but would include full Hit Dice for HP and maybe bonuses to other statistics related to the Paragon Path. In a sense the main difference between an Adventurer and Paragon is that an Adventurer slows advancement while a Paragon continues at a similar pace as 1-10 level, with the addition of more heroic Paragon Talents.
The same kind of bifurcation would occur with an Epic Destiny and, possibly, an Immortal equivalent.
This isn't exact, but I imagine something like this:
The point being, the curve flattens after a new "tier" option is introduced for characters that don't take that new option. All characters start as Adventurer tier and advance at the same pace through 10 levels. Then Adventurers start flattening out while Paragons continue the same pace of advancement. After 20 levels, Adventurers continue at a flatter rate of advancement, while Paragons start flattening out. Etc.
In this variant, all "tiers" have ten full levels and then, after 10 levels, still advance but at a slowed pace.
Maybe this over-complicates things, I don't know. But the thing I like about it is that it allows open-ended advancement for all characters, whether grim-and-gritty or gonzo-style. A 40th level Adventurer-style character would be a wizened old hero, but wouldn't be that much more powerful than at 20th level. But a 40th level Immortal would be a veritable demigod. Both have equivalent experience, and thus level, but the latter character "opened up" Paragon, Epic, and Immortal options. Think of the difference between, say, Odysseus and Achilles or Arthur and Merlin.