This will probably be a controversial point of view, but I think stats – and to a lesser extent, the disparity between equipment tiers – will ultimately prove detrimental to the game. I see a lot of complaint about players with steel griefing sandstone castles, but nobody is touching on a more concerning point: due to stat bloat and how much equipment ramps up, new players have effectively zero chance of defending themselves even with a home turf advantage. I don't think it's an exaggeration to say a mid-20s player in T2 armor and a steel weapon could 10v1 a pack of fresh spawns with stone swords without breaking much of a sweat. Higher levels have no reason to weigh risk vs. reward when going after new players because they know their stat and armor advantage will allow them to easily carry the day; they can mow down noobs like beach imps if they're so inclined. Access to healing potions only makes this worse.
I'm not advocating the complete removal of stats, even though I don't really think they have any place in a game like this. I would ask that Funcom squish them rather than make them more attractive, though. I think stats held up as worthless, like Strength's 1% damage per point, are better balanced than Vitality, which allows a player to potentially quadruple their health pool. Allowing one player to be vastly superior to another solely by merit of his time spent grinding mobs is a bad idea, especially if people really want a skill-based combat system. Progression is fine, this is a matter of the degree of progression. I don't think any player should feel completely assured of victory when flying into a 5v1 even if he's fighting a bunch of nakeds with clubs. The more you allow stat bloat and huge damage/armor differences between equipment tiers to dictate combat effectiveness, the more likely you are to end up with a system where level advantage and superior numbers are the only way to win fights.