I kind of know what you mean, personally I don't like the speed at which and the extent to which dwarves develop their skills - irl the majority of people don't become masters at their skills over a couple of years, they're barely out of apprenticeship by then, and while there is always going to be a pronounced difference between the quality of finished work of a master and apprentice, there is far less of a difference in the rate of work - I can see a master managing to work at three or four times the rate of an apprentice, but the difference in DF is something like an order of magnitude with no penalty to the quality of the finished work, and even worse with high agility modifiers. This is something that I find really grates with me, because it is horribly unrealistic.
Now, I'm not proposing that we cut them right down to the same level as reality, but I think something really needs doing. I mean, right now, once I get one or two fairly agile legendary craftsdwarves in a particular skill, I have absolutely no use for any other dwarves with those skills, because they are so far outclassed.
Now, I can see how this sounds a little off-topic, but if you understand that the main point I am trying to make is that I would like dwarves to take longer to develop their skills, it kind of makes sense. The rate at which your fort develops is related to the skills of your dwarves, after all.
In addition, once dwarves start taking ten years to become masters, all of a sudden your legendary craftsdwarves become completely invaluable and irreplaceble, even if they are nerfed like I would like, because of the quality of goods they guarantee. There would also be a far greater sense of achievement in getting them to that level. And your other dwarves in that profession who haven't quite managed to keep up aren't rendered useless, because they can still work at a reasonable pace.