Re: Aura combat thoughts
School has to be capped or the whole affinity thing makes no sense. It'd be impossible to 'run out of capacity', so to speak, if you can simply train even more.
You should not be able to reinforce aura, otherwise you end up being able to reinforce a manipulation for better manipulation. That'd mean reinforcement can potentially be better at manipulation (or anything else) if it reinforced another school by enough, which makes no sense. I think it just happens most Reinforcement users can consume massive amount of AP at once, but that's not a property of the school. Gon's jajaken consumes 2-4K AP no matter which school he uses, which gives him a pretty significant edge if he was able to use all those schools well. But that's a property of the jajaken, not because he's a Reinforcement user.
What I mean is Netero has say, level 100 Reinforcement and level 80 Emission (at 80% the power compared to a true level 80 Emission) during his prime. This is within the limit of what is possible to learn.
In his prime, he has no reason to use Emission, and based on the flashback, he seems to do mostly hand-to-hand. During his prime, of course his Emission can't match his Reinforcement. Remember that absolutely no one we've seen in HXH that gave a testimoney to Netero's power is alive when Netero was in his prime. Even Zeno only knows of Netero as an old man since he was born, so the fact people say Kannon is his strongest move isn't contradictory, because no one has seen him in his prime.
However, Reinforcement is tied directly to your body, while other schools may be less dependent. I'm sure you decline some other ways too as you get old, but I'd think Reinforcement declines the fastest due to age. This isn't necessarily a bad thing since Reinforcement also gains the most while your body is at physical peak. For example if Shizuku got old, I doubt she'll be unable to vacuum anything. Maybe she can't keep the object materialized for as long, but I don't think the power itself declines. Gon can use paper without having an arm attached, while this is clearly impossible with rock, so I'd think Emission is likewise not as dependent on your body. To put in an extreme way, if your physical attack power is 0 (no arm), your Reinforcement anything has an attack power of 0. But I think we can imagine someone still doing an Emission attack without an arm. It might not be very effective either, but it's not going to be 0.
The numbers I pick are only for illustrative purposes, but I think it's reasonable to assume all schools declines slower than Reinforcement as a function of physical atrophy (and Reinforcement gains the most from physical superiority), so at this point of his life, Netero can deal more damage from other schools compared to his prime. He is ridiculously old so we shouldn't expect him to be able to fight enemies hand-to-hand anymore.
Although the Kannon is inefficient (not primary school), he's fighting guys where he has no chance of winning an endurance fight at all, so he can just concentrate on damage and ignore the inefficiency. You can pretty much say that if Netero's Zero doesn't take out his enemy, he's pretty much dead anyway. Presumably he always saves enough AP left to use the Zero, so the fact that he's wasting AP isn't a big deal. Netero clearly views Zero as his trump card, and whatever extra damage he got in before he had to use it is just a bonus. If the Zero failed to kill someone, do you really expect the regular Kannon hits to kill that guy?
