1/1 Question: Hmm... A lot of rivals that aren't complete jerks seem to be either pretty boring, or annoying(and clearly not intentionally so).
Guess I'll say Silver, simply because it was always satisfying to take him down a notch after seeing his dialogue which, up until he tries to take better care of his pokemon, can be pretty much summed up as: "Blah blah blah weaklings. Blah blah blah strong Pokémon. I'm better than you even though I clearly lost every single battle we had. Blah blah blah!"
2/1 Question: I'll take the water routes from Hoenn, the numerous caves and the slowness of Sinnoh, and the lack of memorable areas and and swarms of Ratatas, Tentacools and Zubats from Kanto.
What do you get? The greatest region ever. 10/10.