Examples of such, please otherwise irrelevant.
Aside from that, I see both side of the scale. Although I will be repping it to show support for the lore as I believe it's a rather extraordinary idea, it has it's flaws.
Ability to maintain physical strength alongside with Necromancy
The ability to, in theory, hold 4 dark arts and maintain ANY strength.
The idea of making them 'fair to fight' doesn't not remain true as anyone with this said art could EASILY necro-drain and stab and run.
My main issue is the physical aspect, however if it's tweaked or comes with it's fair share of debuffs then I believe it should be implemented or atleast given a trial.