Additional Variant Jobs?

[Enkidoh]

The 'Two Jobs from one Class' idea was an experiment that sadly SE determined was a failure a long time ago and hence they have long abandoned any further plans to expand the system - as it is all new Jobs are classless so the idea is moot anyway (and it seems that they're trying to subtly move SCH away from ACN/SMN, suggesting it may be eventually remade into it's own independent Job completely).

And, although your ideas have merit, three of the classes you've mentioned are already kind of in the game anyway in a different form and so would be redundant and the fourth is basically a revival of a class SE scrapped in 1.0 and rolled into GLA/PLD (SE stated they'll never add an actual Necromancer class due to cultural concerns in Asian countries about depicting skeletons and the dead, specifically China - RPR is the compromise and thus the closest that you will ever get to that sort of thing; Berserker is literally a more aggressive WAR; Geomancer is actually what CNJ is called in the Far East (with a little bit of AST on the side); and Bulwark sounds like adding the scrapped Sentinel class from 1.0 to lances (which is an impossibility given lances are considered two-handed weapons and sp prevent a shield in the offhand anyway).

I'm really sorry for pouring cold water on your ideas (and it's clear you have given them a lot of thought), but all too often it's too easy to fall into the trap of coming up with a new class idea, only to end with something that merely rehashes an existing class with a different skin, something that SE themselves are all too mindful of (it's why I'm loathe to make up my own class/Job ideas).