The other day I was explaining the different magi houses to a person who has never played Ars Magica before. To help him understand the differences between houses, I tried to explain them based on the role they perform within the Order of Hermes. I came with the following concepts:
Bonisagus: Magic theoreticians, academicians and Order of Hermes internal politics
Guernicus: Judges, attorneys, prosecutors and lawyers.
Mercere: Messengers, explorer, bankers
Merinita: Relationship with faeries.
Bjornaer: Animists, attuned to the wilderness spirit world
Criamon: Religious, mystics, clergy of the Magic Realm
Flambeau: Army, policeman, warriors, knights
Jerbiton: Relationship with the feudal system
Ex-Miscellanea: Any other wizard concept you need
Then, I realized that I do not have a 'niche' for Tremere and Tytalus wizards. How do you use those houses? What do you think they add to the Order of Hermes?
I would say you are a little off in a couple of houses.
Bonisagus: Researchers, Scientists, and statesmen
Guernicus are Prosecuters and Police beat cops/detectives
Flamebeau: Army, knights, Warriors, police swat teams
Tremere are your lawyers, politicans and lawmakers.
Tytalus are a strange house, they are the gadfly, the conscience in ways, thrillseekers, adventurers. They seek the challenges for sake of being challenged.
For Bonisagus, Guernicus and Flambeau I see your point. I still do not see the Tremere. I thought that lawyers and lawmakers were more a concept for Guernicus. In the case of politicians, aren't they the Trianoma?
What kind of entertainer can be a Tytalus?
Guernicus Justice, strength
Tytali fools, the magician
Tremere the Chariot
Criamon: and the hermit
Bonisagus: the hierophant, temperance (model T.)
flambeau: the sun, the tower
Merinita: the Hanged man, the lovers
bjornaer: the moon, judgement, death
Jerbiton: the stars
ex misc: the high priestess, the devil
mercere: the world
verditius: the emperor
diedne: the empress
I think of them along the lines of
Tremere: standing (professional) army, soldiers; also necromancers
Tytalus: demagogues and sophists, tricksters, meddlers
But also I'd change a few things on your list:
Mercere: the few Gifted are also Mercurian Priests, the "formal" clergy of the Order (whereas the Criamon are more mystics than priests)
Criamon: not clergy of the Magic Realm, so much as gurus
Flambeau: not army or policemen, so much as militia, sheriff deputies, and mercenaries; it is a "medieval", come-on-demand force of knights rather than a professional army like the modern ones.
Jerbiton: add also relationship with the Church and high Art and Academics.
Ex-Miscellanea: especially local, primitive traditions
I'd say Flambeau are the champions, Tremere are the soldiers and legions. The Tytalus chapter of HoH:S lists the following as roles for this house: hedonists, bullies, tyrants, duelists, thrill-seekers, and agents provocateurs (for the Callicleans) or altruists, social reformers, freedom fighters, double agents, and spies (for the Hippians).
Your Jerbiton role is only correct for 4e and earlier. In 5e they are all about beauty, and have been framed as the poets, artists, and entertainers; who use magic to perfect the world.
The Bjornaer Cult is about Ancestor worship rather than animism, and are no more tied to the spirit world than any other magus.
I tend to think of the Flambeau as knights, whereas the Tremere are an army. The former will be more likely to put their own honor and glory over that of their house, whereas the latter will tend to put house first. Similarly, I think the Flambeau tend to have more of a notion of honor, rules of warfare, etc, whereas I've always gotten the impression that the Tremere consider victory more important than the means.
As for Tytalus, I tend to think of them in political terms. If most of the order is made up of libertarians, Bonisagi are democratic socialists (or maybe anarchist communist), Tremere tend toward authoritarian socialism (or perhaps something new we'd have to call oligarchic socialism), then the Tytalus are social darwinist anarchists... an attempted revolution every few years is good for the state, and all that.
Tremere are your lawyers: Rules for the sake of rules, make rules to benefit you. This puts them as lawyers and politicians.
Bonisagus politicals are politics for sake of keeping order together and and unified so more statesmen.
Tremere are also more like your average corporate executives. Keeping the rules, manipulating to advance, keeping those that they can below them to boost their position with all of the corporate politics.
Tremere are organizers, but they promote a different moe of organisation than Guernicans. They are also the most organized House. Hence the distinction between them and Flambeau. Both have large numbers of combat effective magi, but Tremere's are trainded to work together under coherent leadership.
Flambeau are better individual fighters, Tremere are better strategists. Flambeau are better dressed and they get all the girls, while the Tremere sit alone in their labs in angst plotting world domination.
Flambeau are knights. Flamboyant, with panache and flashy stuff.
Tremeres are the ones that get the bad guys dead instead of being killed themselves. The usual rank and file trooper that get the job done. IN everything, not just war.
As usual, amateurs (flambeau) studfy tactics and big flashy stuff. Professionals study logistics. And as usual amateurs are interesting and with charm while professionals would bore you dead. In a battle I would bet for a flambeau. In a war I would bet for a tremere.
Tytalus are just late teenagers: rebels and jerks without a real cause to exist except thinking that the world owes them something. A pitty the house was not marched as a whole when we had the oportunity.
Maybe in earlier editions the Tytalans were just jerks, but its quite clearly not the case in 5th edition (thankfully). I think the vision of House Tytalus provided in Houses of Hermes is the best of the generally quite good lot.
In fact I have noticed the opposite. Before (in my vision at least) tytali magi used to be a opain in the ass. Right now they are a pain in the ass, but of the kind that deserve3s a slap across the face for being a moron. The vision of the house left them being extremely uninteresting for me. In fact we are not using them at all like the way they are in the current edition. And we play in Brittany, so we have Fudarus in our doorstep. We read the chapter, decided we didn't like them and collectively decided that we wanted a baddass bunch of rivals nearby, not a high school full of socially unadapted punks with a real childhood trauma and big guns.
We diodn't like the Criamons as well, since in our opinion the current version leaves the Enigma resolved: so it is nop longer an Enigma. We prefer the more mystical, non defined version of the enigma as it appeared in previous editions. But that is an other matter altogether. In general we like the current incantation of the houses (except the unnecessary rules creep that they seem to suffer) but Tytalians do not float our boat.