I definitely see what you're saying, and I actually calculate throw damage similarly (with a few tweaks for characters with really lopsided damage disparities), but I think it's also important to factor in the amount damage you risk taking should your throw be ducked, etc, compared to how hard you can punish someone for ducking if they expect a throw.
In other words, a character's throw game is really only as strong as his mids.
Example: Cervantes (since I know him best) vs. Astaroth
First, some universals--if the opponent defaults to a crouch for defense, Astaroth's best options for defeating that crouch are 6K and 4B (you can usually see bullrush's startup and stand, though of course not 100% of the time. Still, for the purposes of this example I'll assume you are blocking bullrush on reaction more often than not). While 6K gives good frames, its damage is negligible and it is unsafe. 4B is safe, but it's not very damaging, either, and the frames are poor. In order to do serious damage, then, Astaroth has to start using low grabs.
Now, in Cervantes' case, every throw he ducks means Astaroth takes ~70 damage. Every low throw that whiffs means Astaroth takes ~65 damage. If those same throws connect, there's still a 50% chance of escaping them, whereas if Astaroth chooses the incorrect throw he is losing 1/4 of his life. Now, you might say this is to some degree just the way throw mixups work in Soul Calibur (at least for characters with low throws, anyway), but most characters have a strong enough mid launch that, more often than not, it's smarter most of the time to simply stand and attempt to break a normal throw rather than duck and get launched. Astaroth's mids, by contrast, are primarily annoyances or, in the case of 6K, a setup for another 6K_throw mixup. 6K, this one reliable, non-trivial mid, is unsafe. Cervantes gets aB for about 36 damage.
Before this gets too baroque, let me summarize:
Command throw- Astaroth guesses correctly: 50% chance of doing 70ish damage, on average. Astaroth guesses incorrectly, 100% chance of receiving 70ish damage.
Low throw- Astaroth guesses correctly: 50% chance of doing about 60 damage on average. Astaroth guesses incorrectly, 100% chance of receiving 65ish damage.
While other characters can use the threat of fast, moderate-to-high damage mids to make opponents more often than not stand, thereby making throw attempts "safer" against ducking, Astaroth's best anti-ducking move can be punished for more damage than it in fact inflicts, which makes me feel much freer to simply duck.
So yes, Astaroth's throw game will inject big spikes of damage into matches here and there, but pursuing it exposes him to a great deal of risk. More risk, I'd argue, than many cast members simply because of his rather anemic ability to punish opponents for crouching.
Anyway, does that all make sense? It's late here and I am not feeling particularly eloquent...
