[Thor]

It's always the difference in stats level between players when fighting.

You see much of a difference when changing from 10 to 11 because the players you attack usually only 1-3 levels under or above you, while leveling to 35 in a stats may not have much diff because at higher level the guy in front of you might have up to say, 10 levels under or above you.

In the end, it's levels that matters.

And yes, at higher levels it may take you the same time from 59 to 60 then the neighbor will take to go from 47 to 50 (that's an example!), making him think he's catching up.

p.s. Skills are suppose to have an exponential effect as you level because you always get a bonus over the bonus of the last level, like in Zen's example:
Rank 1 = 2.98 hits per attack for an average of 193.7 total damage
Rank 2 = 3.09 hits per attack for an average of 210.5 total damage
Rank 3 = 3.37 hits per attack for an average of 237.8 total damage
Rank 4 = 3.51 hits per attack for an average of 268.1 total damage
Rank 5 = 3.68 hits per attack for an average of 301.8 total damage

you get + 17dmg at rank 2, +27 at rank 3, + 31 at rank 4, +33 for rank 5 and so on.