I think the biggest missed opportunity with the reboot was the chance to explore an alternate, weak Vergil, which they did a little bit in Vergil's Downfall, but should've been part of the main story too. Something that could've really benefited the story is to have more of a focus on how his lack of training has left him nearly powerless compared to Dante, and how things like Dante having to save him from a relatively weak demon is only making him more and more insecure about his lack of strength. This could build up to his obsession for gaining power. If I were to try and rewrite the reboot's story, I'd have it focus more on this aspect, how Vergil finds that his smarts just aren't enough to make up for the power gap between him and other higher level demons. Even Kat would be growing stronger, as I'd have Dante try to help her better master her gifts as a Medium, but Vergil has plateaued, only being stronger than humans and low level demons. This is why he kills Lilith and by proxy Mundus' spawn, trying to assure himself that he does have power. But using such a cowardly tactic leaves him unfulfilled. He should have been strong enough to slay the spawn in a one on one fight, but had to resort to something so cheap and dishonorable. Seeking the power he needs to stop his insecurities, he then uses the Yamato to connect himself to the Hell Gate after the brothers defeat Mundus. He gains temporary power from this, now rivaling Dante in strength, but his connection isn't fully established yet, and after a hard fought battle, Dante would be able to tap into both his angel and demon power all at once to destroy the hell gate, depriving Vergil of all that power and sending him to the underworld where Vergil's Downfall would begin. At least, that's how I think the story could've been improved. No conspiracies or spiked soda, just a story of two brothers working towards the same goal as their mutual respect slowly turns into begrudging tolerance, and then into resentment leading them both to fight like mortal enemies.