I have made this argument before, and I think it is valid.
The purpose of skill cap is so that people have to choose where to put there skills, and is a good mechanism to keep players with more player time from always dominating in battles. If skills keep going up, some 1000 skill point player would always win against a 500.
However that same effect can be achieved where 'skill points above 600' take an exponential amount of time to go up a point.
So if in 6 months of some moderate use of some activity you could get to 100, it would take a full month to get to 101, and 3 more months to get to 102, and 7 more months to get 103, and a year or more to get to 104.
Those extra points would not count towards the 600 allocatable points.
Why do that? It stops being able to 'template' design, because you can get a few extra points in a skill, yet it still makes it so that effectively, becuase a few points don't make that much difference, there is still the same effects as a skill cap at 100, and total of 600.
It also takes away the idea of 'reaching max skills' and a hard core grinder could get a few extra points, but its effectiveness would be minimal other then a record of time using that skill.
It also is why the grind from 40 to 50 in original MMOs was so long. and why the original D&D stat grind to 25 or above was so difficult.
The main idea is make there no max, but effectively a max by the exponential leveling above 100 in a skill, or total of 600 skill points.
There is no downside to using that methods since game is a skill game and a couple points don't make that much of a difference, and full of win in using that method, since it removes automatic constraints, and the idea of templating a maximum spending of skills for a maximum effect. Since you would gain maybe an extra point or two every few months after reaching max level.
It also gives an added record of permanence, with very little actual effect to a player character abilities, but a visual record of play time. Titles for each added point above 100, and 600 could be available to show the actual player skill(not stat bonus) in such areas from the huge amount of experience in those fields.
And those that want to grind to max, would not have an end to reach, and it would mess with the idea of grinding to max skill as a goal, since there technically would not be a max.
I know you have many features to think about in the game and work to do, but it really is a valid idea.
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