I think there's 2 things that make this work for EVE online that make it not so good for other types of games.

1) The time-to-skill is exponential time == linear percentage of skill's effect. Unlike a WoWesque RPG, there's only 5 levels to each EVE skill, each representing 20% of the total power of the skill. That mean skill curves look like 15min == 20%, 60min = 40%, 4h = 60%, 16hr = 80%, 2.6d = 100%. That means that you're up to near full effectiveness in a short time, if you flush out the right set of skills use the better equipment you're almost as good as a top leveled player. Thats right, spending your time correctly on the 14 day trial, you can fly the smallest ships > 80% as well as the oldest characters on the server.

2) Combine that with EVE's fairly flat power curves and hard-counter systems you can easily pick your battles to own up on much more veteran players. That's like saying a level 30 WoW character can kill a level 80, with the time-to-skill more or less replacing the need to pick a "class" at game start. Eve's basic ships only get so strong, and many of the skill bonuses are actually things like "1% better per level of X". Something like 1% more HP doesn't actually buy you much, but it's still an edge you can leverage. Stack everything, and maybe you're ship is 200% better fully skilled than it is basically skilled, but that still only 200% better than the tier of ship you're using. A frigate is a frigate, and all the hitpoints in the game will let you have can't keep you from death at the hands of an anti-frig built destroyer. If you play to the counters, a super-skilled and decked out ship only starts to stand a chance against weak setups designed to counter it. And often times, you don't know if you're going up against a counter-fit-ship (since eve's fitting and skills are generally hidden variables unlike say WoW's equipment and character classes) so you just have to cross your fingers that the type of ship you're hitting is as juicy of a target as it looks.

I stopped playing EVE many years ago, but when I played I enjoyed the time-based system. For one thing it was something new, and all else being equal I like seeing new approaches to things. More importantly, I didn't have nearly the time to dump into the game that a lot of players did, and this helped keep me on par with them. Obviously they outstripped me quickly in physical assets like money and ships, but I was "gifted" a lot of that due to being valuable to my corporation (and later, alliance), so that helped as well.

I would have liked to see a system where it was even harder to get certain key skills, so that a player really had to focus in on a certain set of ships and abilities. But then, my "dream MMO" wouldn't be very popular, cuz I keep wanting to make things harder...