Those are already pretty well thouhgt out, and well done in my opinion. Armor instead of pure random chance, and a limited number of source points rather than "Haha all the strongest skills can be used as openers for EVERY combat."
This sadly ignores a lot of it's shortcomings. For example it creates a great imbalance regarding the distribution of it's effects. For example it's "all or nothing" makes vitality a lot less meaningful up to completely meaningless, as armor up or down determines often about win or loss thanks to the heavy CC. (damage doesn't "reach" life as long as armor is up, and is of no use if not, as acting isn't possible at all most times [knock, stun, freeze...])
Same goes for source points, the advantage exists unchanged. The question "opener" or not is simply not about the source points as a resource, but instead about the powerdifferential between these skills and non-source ones. An imbalance that exists only just of that and shouldn't after all!
In other words: Would you like to start a duel with no source while your opponent has the maximum? I doubt that...
