So this is purely a speculatory subject, but I figured I'd see what other people may know/think about the two factions left over after the Mages' Guild dissolved.

If you read the Infernal City, you'd know that it is mentioned a few times about how the guild split. The remains of the guild organized into two separate factions, which leads me to believe that they do not see eye-to-eye. By all logic, if you have an organization that splits into different groups, you can only assume that it was over an issue they did not agree upon. My main question is what that is.

I've forgotten some of the details from the book (which I should probably re-read soon), so my information may be lacking. I don't recall any specifics mentioned about the two groups; only that they are what remains of the Mages' Guild and their names. Concerning their names, the College of Whispers doesn't reveal that much on name alone. It is best to interpret it so far as what Synod isn't. A synod in the real world, according to a few places on da interwebz, is a religious organization, specifically a meeting between religious officials. Making the logical assumption that the Synod of Elder Scrolls was named after the same term of synod used in the real world, one can guess that Synod is a religious group. And because it is a remnant of the Mages' Guild, it is a religous group devoted to the teaching of magic.

Taking that information, that leads me to believe that the College of Whispers is probably a secular organization to contrast with Synod. Another possibility is that, instead of being secular, it lies on the opposite spectrum of religion and morality as Synod, or at the very least skirting the edge. From the only encounter with a member of the College of Whispers in the Infernal City, I don't believe they are outright evil due to the fact that they are permitted to operate within the confines of society and don't seem to be up to anything dangerous and malicious. But the fact that an agent of the emperor was sent to kill said member of the organization leads me to question why the Empire is acting against them. It may just be that this one individual from the College of Whispers had a hidden agenda, but I don't recall reading any such thing in the book.

From the less extreme views of both groups, it may be that Synod is a magic-using group dedicated to stopping evil magic users like Necromancers and the College of Whispers is a secular group devoted to the furthering of knowledge, even if on an uncertain moral ground. Going with a more extreme view of each guild, you can assume that Synod is an extension of the church, fitting the role of healers and such. Or, the College of Whispers is a risky organization that dabbles in darker magic, even in secret (could explain the "Whispers" part of the name). If the latter options are the case, then you are left with organizations reminiscent of the Temple and House Telvanni from Morrowind. Or it could be any combination listed, while either group can also fit the "neutral" role in a pseudo-contrast with the more extreme organization (The old guild of mages to House Telvanni, or the guild to the Temple)

Given these potential differences between the two groups, it narrows the possibilities of why the old Guild of Mages split up. I suppose that's free speculation. So, if you have any other thoughts to add or facts to state, enlighten me. This is probably the biggest question I have about the future in Skyrim, as I play mostly magic-user characters. The more that is revealed, the better.

Edit: It occurs to me that I misspelled "remnants". I now feel terrible about myself...

The Synod are the police, the College are the anarchists. By my reckoning. Anything else is confusion.

thank you i find your information insightful

And where is Saffron Park? Balfiera, perhaps.

could be cool and have a faction system like FO:NV