TL/DR: Significant power progression good, vets encouraged to stomp noobs bad, increasing risk vs reward good.

I don't think CCP should shy away from a progression system that significantly powers up a character, like it does in Dust. This is an MMO aspect that really keeps people invested.

Yes the gear and passive skill disparity in Dust between vets and new players was a problem, I find it more an issue with mixing new players and vets than a problem with the progression system itself. If I was going to criticise dust's system I'd say it took too long to unlock the higher level skills, rather than the skills being a problem. Though I agree that %damage increases don't really make much sense lore-wise.

The higher isk cost helped mitigate the power of high level gear, which I really like. But in the end, especially with the vast wealth available from PC, this element further pushed the gap between those who could aford expensive gear and those that couldn't.

I've been playing a lot of Hearthstone recently, which is a lot more similar to Dust than you might imagine. That game has a massive power discrepency between new players and veterans / pay-2-win players. But that power-gap also means that you can feel a significant progression as you play. Also, as you are generally matchmade against similar level players you don't get crushed all the time. It's helped by the 1v1 format so there's no relying on blueberries.

I guess my point is, I'm worried that without a certain amount of power progression people may not be as invested.

Part of the problem with Dust was that vets stomped noobs, and were rewarded for it. How about this for an idea, inspired by other MMOs:

Players can choose from high-sec or low-sec matches.
In high-sec you can skill up gear from level 1 to 3 but not beyond. Only level 1-3 gear can be used.
In low-sec any gear can be used and gear can be leveled from 3 to 5.

If ISK is a thing (which I hope it is), rewards in low-sec would be significantly greater than high-sec, as to render high-sec effectlively worthless to veterans unless they are skilling up gear from low levels. Matchmaking should also exist within tiers.

By the way, death costing you ISK is an issue as it breeds cowardice. Something to think about if CCP carry this aspect over.

It's worth noting, part of the progression in Hearthstone is the opening up options to build decks with powerful combinations, rather than just more powerful cards. It sounds like Nova's proposed progression of opening up options may work in a similar way.