I'll toss in my version of the truth - it's fun seeing how others do it.
Most of my Shek P'var are just like Leitchy's - scholars with no interest in the real world. They know a couple tricks and some can foretell the future, but for the most part they are seen as worthless to the average man on the street. If one can reliably tell the future, make potions and poultices that work, or do something entertaining, they are well received by the public, and are regularly sought out. If they have no "worthwhile" talents, then at least they sometimes teach the kids to write and do numbers, and that's worthwhile. If they want to bury their heads in old scrolls on their own time, well, it keeps them out of trouble. The public knows where the chantries of magic are located. Given the scarcity of chantries, most people never meet a mage, but they know they exist. The average person doesn't have a realistic idea of what a mage can do, but there are generally held stories about what they can and cannot do. The popularity of mages varies with how helpful they have been lately. There is at least one Genin-type walking around any given year helping out the common folk somewhere on Harn, but he was one of the very few that got widespread notice.
Some chantries and/or associations of chantries have numerous rules about what you can and cannot do. This includes the types of magic that can be used (necromancy is bad, but divination is good!), treatment and teaching of students, magical use in the public eye, etc. Some of this is basic common sense, other rules are to keep the mages out of trouble, and some is just to increase the political power of the group or the leader. Because there is no Mangai in my pHarn, there is also no over-arching mages guild of GoAL. The White Hand is no more than the enforcement arm of the Cherefir mage's guild, and thus has limited power. They are the biggest group, and throw their weight around accordingly, but don't have anywhere near the power they like to claim. Sure, the guild houses in Aleath and Thay follow their lead, but Glenoth, Coranan, and Tashal ignore them and go their own way. Mages follow the rules of their chantry because they find them to be good rules, or because the benefits of being associated with that chantry far outweigh the hassle of the rules.
As for the Council of Eleven, they started out as a group of people that were very interested in a) the wise use of magic for the public good, and b) good relationships with the elves and dwarves. They are still very interested in these two things. Their current working projects are the consolidation of Harnic kingdoms and integrating the various barbarian tribes into the more civilized societies. Unfortunately, they can't decide who should get Chybisa, and there are at least 5 competing views on how western Harn should be reintegrated into one Empire. None think the Solori or Pagaelin worth keeping, but they have hopes for the Tulwyn, Kath, and Bujoc. None of the current group have interests in Orbaal, and so that region is ignored. When they can all agree on a course of action (uncommon) they can be quite effective, but their real ability is the widespread intelligence gathering network they have. Friends, former apprentices, and paid spies feed info to the various members, and they generally share all they get with everyone else in the council. Sometimes they are aligned with the Melderyni crown, but not always. Sometimes the Melderyni crown knows about them, and may even be a member, but this is rare. Chunel likes them because he knows he will get quality intelligence from them, and greatly values the differing viewpoints on any course of action. They enjoy meddling in the affairs of others, and have the power and/or money to do so. They prefer being the power behind the throne, whispering in the ear of others.
Diviners and fortunetellers had warned something bad was coming to Thay, but as always, couldn't give specifics. A gargun swarm was about the most anyone thought about, and they were thought to be crazy end-of-the-world types. There was a lot of finger pointing afterwards, to be sure. As soon as they hit, they yelled for help. Riders were sent out, and boats fled for safer ports and to spread the news. Cherefir knew Thay was in trouble the day the raiders came into view, but could do little. The first time, the stars weren't aligned right, weather patterns were all wrong, and the big guy was down with the flu. When they came back, it was different. The storm was natural, and would have torn up the raiders regardless, but the mages in Cherefir were able to nudge it in just the right way. A week before or after, and they would have been powerless to help. They'll never admit that openly, of course.