I've been wanting to pick up Sun God as my first go at Kotal and for the reasons you just said I feel like he's supposed to be played as a defensive pillar based around his Sun Ray/Beam(whatever the healing one is called), not his command grab.
It seems to me that you want end your combo with B34(I think that's that one that sends them fullish screen) into the Sun Ray(And I know that isn't a completely safe set-up, but that goes with the meta/mindgame), then use Sun Disks for conditioning their approach.
He seems like he should be difficult to open up on paper, even more so if he has a bar of meter. Just stand in the healing ray to force movement from your opponent while you heal. They can't jump in because of his air grab, his buttons have ridiculous range so he has great footsies, and he has his parry.
I'm sure you guys that Kotal know about this, but when I was practicing a different character on a very hard bot, it parried my string into ex command grab for the armor.
(I never knew you could do that).
Having the ability to parry into armor means the opponent must be very respectful on incoming(not sure if it counters armor though) if Kotal has a bar, and with 2 bar, you can have a 2 frame start up parry into an armored throw. Even though the damage is small, this can be HUGE in closing situations, especially if you're sitting on level three sun level or whatever it's called, possibly with the damage buff too.
The potential to do things like that is why I believe the lower damage on the command grab is justified, even though I think the base damage could probably start a bit higher, even if it still caps at 16% at level three.
So his defensive options, healing and buffs, coupled with button range, I get why he doesn't have ridiculous options for opening you up. He seems like a defensive footsie character, meant to play a more reactive play style rather than a proactive one.
All that being said, I don't play the character, yet. Do any of you guys that have played him more know a reason why playing this type of style with him wouldn't really work? Seems good on paper, but I know that doesn't mean it can actually work in game.