I think that any kind of suggestion are valid, but I honestly don't agree with you on your both suggestions. Yeah, the idea of a harder game was fortunately accepted for some players, including me, but first you need to understand that will be more stronger NPCs than just elite four. Gaining exp in the end of each battle instead of each pokemon defeated would be unfair, especially for those people who wish training a low lvl pokemon. So, I'm in Viridian Forest training any new weak pokémon and if I wont kill all the NPCs pokémon, I won't supposed gain any exp? Sometimes we like to train a few pokes at the same time and a weak place is perfect for that training. And for those hard battles, if you could killed a Mega Pokémon, for example, and almost all of your team are dead, but anyway, you did, you killed it... I supposed got this exp. So, waiting the rest of NPCs team that can, somehow, kill my survivors pokes, just to gain my fair exp won't be a nice idea because this exp wouldn't be guaranteed.
Besides, I think the cooldown of each NPC need to be readjusted for what kind of place they are and its functionality there. With this suggestion, a victory road NPC would have the same cooldown of youngster Joey, this seems unfair at all.
About the system's announcement, if a player could have an option to able or disable this messages, like you said, it's ok for me. But if we can't, I agree with Engineer. Some people won't like their achievements revealed into the public. Badges achievements and things like that won't be so problematic, but hard pokes and shiny pokes caught would mean some headache, believe me.