1. I personally agree with you here. Now that the Link and Chain systems provide incentives for doing grinding well, I wouldn't mind it taking a bit longer to get to 50, especially since there are many activities designed for middle levels.

2. Meh. People who are power-leveling are missing the opportunity to really learn their class by 50. Sure they can catch up, but you end up initially with players at 50 who don't even know all of their abilities. This could be irritating when it's easier to form groups for end-game content, but right now it's not really a problem for me.

3. I understand your concern here, but I don't think they should make changes. The stronghold bosses were not designed for parties of 8, so we would need an alliance system to tackle them without these changes to the claim system. Yes, abuse of the system could be a problem, but I haven't heard of your scenario happening so far.