I'm not quite following how this is supposed to work. You have a whole bunch of abilities and prerequisites and stated plans for 6 classes. I don't see how this all comes together, yet. d20 Modern style classes, so mostly a chassis with talents on the odd levels and bonus feats on the even levels, maybe mixed with a few minor class features here and there?
Yeah, pretty much.
The idea is that SAGA classes are for the most part, fairly balanced. Scoundrel is equal to Soldier is equal to Scout, at least in their role. The only odd duck is Jedi, but that's because they're a caster in a system without casters.
Generally speaking, I'm hesitant about that style of classes, at least within the context of D&D (and especially when comparing them to D&D classes). Half of your abilities are things that anyone can do (feats). The other half are picked from a broad menu, which produces reduced overall coherence and synergy compared to a tailored suite. The paradigm also tends towards feature-light classes, resulting in characters whose capabilities are defined more from external sources like the equipment they use than from internal sources like personal strengths and heroics. Not to say that this will result in the same, just a warning of what to avoid.
I might cut the number of feats from classes down significantly, from the planned to possibly 4. That will ease some feat constraints, while not making them overwhelmingly common.
With the "Tree" set up, I'd think talents would be more coherent, allowing people to build the character the envision without being forced to multiclass. Of course, it's viable to multiclass, but that's a
For Fighter-Types (Warrior, Rogue, Spellblade), I plan on giving them disciplines of choice to differentiate them from each other further. Like 5 Ex for Warrior, 3 Ex for Rogue, and 3 of Ex or Su for Spellblade. That will make them more varied than they'd otherwise be, even with my improvements to the normal fighting styles. That lets them be somewhat different from any others.
Mages, well, the spell list is being given a look-at, and thought about. For the most part, I'm taking the most iconic stuff, and slapping on some other stuff that's suitable for them.
I suppose I could steal PF's Words of Power system for spell creation as a base and allow people to make their own spells...
And for experts, I don't have a damn clue. I need something to boost them in a way similar to spells/maneuvers.
Or I could give in to the "I have gear" part, and make them be the Batman to the others' Aquaman and... Don't know who, but anyway. Give 'em gear as their gimmick, and let them make up for no special ability with improved uses, ect. Or skill tricks.