10.30 and below has a arm 11 kernel exploit that allows you to downgrade but the arm 11 kerenl exploit should be used on homebrew to give apps it so they run better and even on 9.2 which im using for cfw you have to use ninjahax in order to get kernel access on home brew launcher since thats the only one hax 1.1 works on which is only homebrew launcher hax that has kernel access
To answer the question of "why are we not using the ARM11 exploit recently found to improve the quality of homebrew on 10.3", the answer is that the ARM11 exploit isn't fully developed yet. That is why so many people had problems initially when downgrading. Once it it officially released and people are able to use it safely, I have a feeling more homebrew will be able to use it.
That being said, it likely won't make homebrew "faster", but it will enable a few features that homebrew apps didn't have access to before.