I disagree. I can think of several problems to level-synching.
First (and in my opinion most importantly), it would take a significant amount of time to develop, code, test, and implement a level-synching system in FFXIV. I'd prefer that we get content now. If they want to implement level synch, they can do it later. For now, I'd prefer to have more stuff to do in the game. Please, pretty please don't make me wait 3 more months for two dungeons.
Second, you're forcing everyone to play the game the way that you find most enjoyable. You're obviously a hard core player. I definitely wasn't the first anything on my server. (Congrats, by the way

) So you obviously enjoy challenges. And while I'm like you in the sense that I enjoy a challenge, there are lots of folks who play the game much more casually. They don't want to spend the time figuring out the minutiae of their class, and finding the best players to party with. I have no problems with casual players going through the dungeons on r50s if that makes the game more enjoyable for them. I'd just prefer that they stay in the game.
Third, I'll have to buy and start carrying around two sets of gear and armor for each class I have over level 30. That will make my inventory management problems worse.
Fourth, my macros will be useless. For every class over 30, I'll have to go through and set up an entirely new set of r30 macros. Considering I'm already forced to set up 3 sets of WS macros for every class, plus another macro set for armor, ... well, that's a headache I'd prefer to avoid.
I'm sure there are other issues, but I've droned on long enough. My point is simply that it's not a cut and dry issue. There are definite problems with level-synching, too.