Yeah definitely going to be a must for balance testing.
Can already see some concerns, just as the scribing glyph for oblivion damage.
For Soul Burst:
"8% of your targets Max health as oblivion damage, this damage doubles if your opponent is below 50% health".
On a typical 35k health setup, that's 5600 oblivion damage (as a secondary effect not including the base damage of the skill).
I like the concept of punishing health stacking in cyrodiil which is what it looks like this is trying to do. But we've tried hard hitting oblivion damage sets in the past and they always get nerfed because they are too strong. Maybe push the threshold down to 25% health for the bonus damage to be in line with other executes.
But despite that an AoE, oblivion damage execute sounds like a problem.