I honestly don't know where to begin with your first point, but you have to realize how silly it is to want to protect players from themselves. As a company, you have a ToS that players agree to, and it's up to them to play the game responsibly. It's like saying they should remove reg server so that irresponsible players can't get themselves in debt trying to be the best. Does that make sense to you? If players lose the ability or motivation to grind in MapleStory, they might quit and go do it in a different game that is more rewarding for their time. Sweats are a necessary part of any game, and 99.9% of them don't need protection from themselves. So why make a change to benefit the 0.01%? Imagine the top richest 0.01% people in the world got a free pass on paying taxes. Ironically, it doesn't add up.
"2. Speeds up Sol Erda progression for everyone else in the game, the vast majourity of players will progress faster each day with a daily system."
How does having a cap speed up anything for anyone? Even if there isn't a cap, you can still just grind for x minutes per day to still receive 400 Erda Energy. Heck, you can make that your own personal daily goal, and this way it wouldn't interrupt or interfere with anyone else's progression while you would still be taking nearly 2 years to max your skill out. Removing the cap allows those who enjoy grinding for longer periods of time to progress further into 6th job at a faster rate (obviously). In which case I ask you, why shouldn't the players in a MMO be rewarded for their time? You said someone outed themselves for being "12 year old little timmy", but clearly what you're really worried about is being gapped.
You can't play as much as some other players, and that's okay. You don't need to compete and compare yourself and your own progression to the rest of the player base; because I'm certain that you aren't anywhere close to being number 1 in any server (given your take) anyway. Therefore, being on the same slow progression path of 6th job as others wouldn most likely not help you get any closer.
Even the second best player in the world is being gapped by the first best player. That's why he's second. Get over yourself and realize the bigger picture and how detrimental this cap can and will be in a game like MapleStory. Even if you still think you are right, look at what the vast majority of others are saying. Surely the people who actually play the game a lot should have the benefit of the doubt in this situation, no?