Can you tell me the purpose of labeling a Gladiator with Red Mage title ?
We can already tell with 90% accuracy that Red Mage skills won't be equippable cross-class.
You can already equip Thaumaturge and Conjurer skills on your Gladiator you know (which is the rough equivalent of having a level 37 subjob if you want FFXI example). Your Paladin might even have "astral magic affinity trait" that will enhance these base spells.
And we don't know about weapons yet. Specialisations might not allow completely new weapons (only variants, ex: Marauder having Dark Knight job allows to use Scythes which is only a variant of a Great Axe) since the base classes are weapon specialists.
As far as we know, jobs only draw the line of a class roles, there are not classes.
You can take a look at this old chart that was made few months ago, that may be the kind of path SE is taking.
http://imageshack.us/photo/my-images/638/gridv.png/
