@Second Saint I play Sun God and I feel he is very reliant on metre.
In combos it's all about getting that EX air grab to extend them so you can do maximum damage.
Then there is the occasional EX projectile to end a short combo or catch someone off-guard.
On defence/offence it's about being able to do that armoured command grab (moon god choke).
And on defence that EX parry can help turn the tide against an opponent pressuring you.
I almost never spend metre on sun rays and I never spend metre on his health-gaining soul scorch move.
Combos that require more than 1 bar of metre seem unpopular with nearly every character in this game so far.
As far as I'm aware Sun God Kotal does not have an EX combo starter at all so metre doesn't matter much to him in that regard. At the same time, War God's EX sword overhead is one of the main reasons he's viable in tournaments if you ask me.
On a final note, if I can get an extra 11% of damage for 1 metre I will usually take it.