Hmmm, and how old exactly is the Main when he goes into servitude, Craig? It's just that from the remarks that the Main makes in TRPG2, I would say the Main is actually older than Duvalier, or, at least, more mature. There is also that business with Grotius, where the Main may answer in an off-hand way about having no time to deal with teenage drama- it sort of implies that the Main is past this stage. Then there is aslo the attitude of other teammates towards the Main- even if the Main is a brilliant and talented Psy, a very young age surely would imply a respectful politness, but of a different sort. Then there is the fact that the Main has been in Shadowling captivity for 4 years- can it be that by the end of TRPG2, the Main is older than Duvalier at the beginning of TSoG? This also begs the question: at what age, typically, do the students get enrolled into the Academy, get their Blue Capes then get their Black Capes?
With regards to potential and strength, assuming TRPG2 Hero is younger than the rest of the lot and that his creativity/talent, rather then strength, was impeded by the bracelet, and the fact that the Main could learn Vengeance, Pyro Hail, and Big Shield, I'd say the Main had the most potential, but may not have been the strongest of the lot.