To address your points.
A) Korea is dominating. ---- Korea practices more..... NA and EU teams practice around 6-8 hours a day. KR teams practice 10-12 hours a day. over the course of 1 week that is already upwards of 42 more hours a week of practice. Also the region is more competitive so players get a better challenge over there. basically Korea is gonna win because hard work and dedication. Riot cant do anything about that.
B) The same small champ pool. ---- META -> Most Effective Tactic Available. they play the small pool because they are the strongest picks. and to address your point on the champ cap. Capping champions will make the scene less competitive. Why you may ask? well this is because if 1 team picks something crazy strong for them then they have to play something shit next game because banning phase. then the enemy team gets a stomp. this system would make for every other game to be a stomp. Not to mention having pocket picks is something that helps worse teams win and if they can only pull out the pocket picks once per series then they are doomed.
TLDR on B ---> Putting a cap on champs only hurts the bad teams and makes the games even more of stomps making the game even more boring to watch.
Also are you trying to say that the only way the game is fun to watch is if everyone is constantly on death timers because its a super bloody game? you have to understand that there is a huge part of the fan base that loves the slow paced games. I personally like the games where the teams are in standoffs and 1 mistake costs them the game, but if the game is super bloody usually it doesn't come down to one fight.
TLDR....again....: in the end LCS and worlds aren't boring. You find them boring. and that's a you problem. not a riot problem