I believe that if the goal for skill gain is to encourage "normal" play, then this would be a good solution to achieve that, without taking away powergamers gains, or taking away casual players gains.
1. Powerhour concept gone completely.
2. Gains only on success (beyond 70 skill) of a similarly difficult action for that skill (where relevent)
3. Rate over time concept (but not the way it used to be implemented on SP).
The Rate over time concept should be the "playing time" not the "server" or "real" time. Server or real time only encourages logging in and out periodically to get your "guaranteed" skill gain (which rendors this option useless for the goal of "normal" game play). However, if you have a setting of, say 5 minutes per .1 gain from 70.0 - 79.9, 10 minutes per gain from 80.0 - 89.9, 20 minutes per gain from 90.0 - 98.9 and 30 minutes per gain from 99.0 - 100.0 of actual playing time, then a player will have no use for repeated (macroing) use of a skill to gain their skill. At high levels, they would have a need to go do something else (on this character, in game) while they wait for their time to expire for that skill. The "something else" could easily be, using ANOTHER skill on that character.
Also, you don't have to make the skill gain "guaranteed" after the time expires, but instead "possible". So, just because you sit at the bank for 10 minutes talking since your last FS spell, you don't cast one FS and get your next gain, you may have to cast several spells before you actually get your gain, but the fact that the timer expires, means that you now have a chance of gaining.
In this type of gain system, a mage, who camps out in a dungeon, would be periodically gaining skill in magery, eval intel, meditation, resist, healing, anatomy, wrestling, just for fighting monsters in the dungeon. This would be TRUE "normal" game play, and it would allow the person to gain while their at it. At high levels, they wouldn't gain very fast, but they would surely gain every time their clock time passed, since they are using all of those skills all of the time. In this system, you would see no more mages on a boat (unless their fishing
Currently, if you want to gain magery fast, you get on a boat, 8x8, WASTE a ton of regs, and boom, your a GM. It is not only BORING, but WASTEFUL and ANNOYING (not to mention the complete opposite of "normal"). But it is currently the only effective way to GM a mage. Believe me, I would much rather be spending my time casting EV on a drake or FSing a lich to gain my skills to GM. At least I could cover the cost of my regs.
Likewise, a warrior would gain periodically in their skills by using them over play time in a dungeon.
Mule characters would have a harder time with this system, since macroing would be really non-effective (or non-efficient anyway) unless they are filling an order. Most mule characters are working a number of skills anyway, so they could simply move from skill to skill to get their gains in that skill.
This type of system would work for both powergamers (who will continue to gain periodically no matter how long they play) as well as casual players (who would periodically gain the entire time they play, whether it's 4 hours one night a week, or 1 hour four nights a week).
I don't know about the rest of you (but I'm sure I will soon
but I personally would LOVE a skill gain system like this. I think (certainly for me) it would make the game fun again, because I wouldn't have to worry or care about powerhouring to gain skill, I would know that by simply playing the game, I would gain skill at every level. And THAT, would be fun.