I'd say you're on the right track Othin.
Trickster being able to use magic would certainly give a big incentive to use them in comparison to Rogue's when pit up against Assasin. From the looks of things, it truly seems that they are aiming for all possible weapon/magic combinations. Consolidating magic into a single category was probably done to enable this without the need for sword/anima sword/light sword/dark etc. for each combination.
Hm, there's a way to look at the blend. I figured they just did it because they were sticking with the blend, but that could make sense.
The main concern, the way I see it, is bows. I don't expect we'll see anything with bow/tome or bow/staff, and bow/lance seems difficult to fit in. They managed it in FE11/12 with Generals, a clear attempt at filling in the last edge of the tetrahedron, but that seemed forced, and Generals don't appear to use bows now. This is kind of a concern, with how shafted bows were in FE8: they were only used by Archers, Snipers, Rangers, and Warriors, and each class was uncommon enough that bow users turned out rather rare.
Thanks. A quick count showed 41 classes, so if any more show up, it's only a bonus.
We already know that more classes than that must exist anyway.
Lord --> ???
Strategist --> ???
Manakete
Taguel
Dancer
Cavalier --> Paladin / Great Knight
Knight --> Great Knight / General
Pegasus Knight --> Falcon Knight / Dark Pegasus
Dragon Knight --> Dragon Master / Griffin Knight
Archer --> Sniper(?) / Horseman
Mercenary --> Horseman(?) / Hero(?)
Fighter --> Hero / Warrior(?)
Brigand --> Warrior (?) / Berserker (?)
Myrmidon --> Swordmaster / Assassin
Thief --> Assassin / Trickster
Mage --> Sage / Dark Knight
Priest --> Sage / Battle Monk
Cleric --> Sage / Battle Cleric
Troubadour --> Valkyrie (?) / Mage Knight (?)
Villager (?)
Marth (?)
That looks like about 44, with the possibility of more. I don't think we'll be seeing a Dark Mage class.
What if Trickster was an optional branch of a dancer? I want the dancer to have some options too, but I bet it'll be more like the manakete we saw where it's a single class that will have other options with the class-change. A dancer with any sort of weapon or even staff would be cool.

Trickster is the boxed class. The class that promotes to it is Thief; the alternate promotion is Assassin.
I don't think we'll be seeing the option to have Callum, Gaia, and plenty of other characters gain Dancer abilities.
Edited by Othin, 28 March 2012 - 02:40 PM.