Koya would probably be very popular if he was a character in the anime or the games and more people knew about him, and yeah, his motivation made so much more sense than Paul's whose whole thing, like you said, was basically "Oh geez my brother got all the badges of 4 different regions and 6 Frontier symbols...but who cares...he couldn't beat one opponent who's known to be one of the strongest trainers ever...he's weak and his methods won't work."
Yeah, Apocalymon was such a joke in the dub version. I mean, he was the final boss of the anime and he was completely overshadowed in the creepiness department by Myotismon/VenomMyotismon, Piedmon, and Machinedramon in terms of creepiness. I mean, if the dub could treat those characters with so much respect when they were all tests for the Digidestined before the final villain, why butcher Apocalymon so much? I mean even the dubbers felt that Apocalymon was creepier than the other villains when watching the original and decided he needed some toning down, that's fine...but Jesus...why tone him down that much?