I agree with the concept and I encourage you to pursue this change...but
to be quite honest, I don't think I understand just how you propose
going about "switching" skills. The skills that you posess were taught
to you and aren't likely to be easily "forgotten". You ask why you have
the ability to exterminate at all. Well, as you study the realm of death
through necromancy, so you have gained that ability as it's in
Necromancy's teachings.

The skills in necromancy are centered around death and, for the
most-part, work towards death itself. I would be more than impressed if
you could mold it into something that would defy death and actually
bring life, considering its nature.

It's a difficult thing to speak on general, worldly imbalances. To say
there is an imbalance in the realm because half the people can do
something the other half cannot is not entirely correct. We, each of us,
choose what we study in our lives and we can only maintain knowledge of
arts in certain domains at any given time - that is the nature of
things. Just as Druids and others can use skills of resurrection, so can
necromancers use skills of destruction. They are opposite sides of the
same circle, and as such, they can't share attributes or in this case,
skills.

All the same, good luck to you. It may work in the end.

Penned by my hand on the 4th of Arios, in the year 179 MA.