I've been fiddling and experimenting with the character generation system for Mythras since writing this post, and here's what I've decided to use for skills in Dawnlands games. To me, this combines the ideal amount of customisation with speed and ease. I'm also including some passion house rules that make them easier to calculate (and slightly lower on average) than the stock rules.
Starting PCs pick seven standard skills, seven professional skills, and one combat style. They can swap out one professional skill choice to get a second combat style choice. They get 350 points, and can spend up to 45 points on any skill, adding 1% per point spent. They also add +40% to their Native Tongue and Customs skills.
Starting PCs also pick three passions. The first passion has an initial rating of POWx5, the second has an initial rating of POWx4, and the third's initial rating is POWx3. Skill points may also be spent increasing passions as if they were skills. PCs may also swap out one professional skill choice for a fourth passion, which has an initial rating of POWx5.
Art, Culture, Craft, Languages, Literacy, Lore, and Musicianship each have a number of specialties. Customs is the equivalent of Culture for a character's home culture, and Native Tongue is the equivalent of Languages for a character's home culture, but Customs and Native Tongue are distinguished by not having specialties. A character with these skills has a number of specialties equal to 1/5th the skill. Characters test their specialties at full. Outside their specialties, any tests with the skill are at least one grade harder.
One side effect of these passion rules is that most spellcasters are going to start off a little obsessive. I consider this a feature, not a bug.