So as to not clutter the forums with a new thread with a topic very similar, I wanted to post an idea on the levels required for elemental area shield.
I reached blast lvl 10, and shield level 0, and still the area shield was availabe. I figured it would be easier to get the area shield through leveling the shield, (lucent in my case), so I think the unlock is close to
Blast lvl + Shield lvl*2 (or maybe 3 or 4) = 10
Or depending on how you look at it,
Blast lvl/2 + Shield lvl = 5.
To verify this, I would have to know how how high a shield level you have to have to get area shield without leveling your blast.