Well it all just achieves the same thing. The developers can give you "something to do" regardless of which option they take.
- if there were no ranks, they would give you meaningful battles, quests, objectives, and a wealth of content to digest.
- if there were ranks, then they would give you meaningless battles just to fill out your SP bar (think grinding), and less content to digest.
Anyway if endgame starts at day one, then you aren't "Racing to endgame". To the contrary, you have all the time in the world to digest the content the developers put into the game, and you wouldn't be beleagured by the constant nagging voice telling you to "level, level, level" before you could actually have fun. You could take it slow and just see all there is to see in the world and do all there is to do.
But, really, think about it. If the game is so devoid of actual things to do that it has to resort to forcing you to rank up for no other reason than to waste your time, then that's just poor development.
Theoretically speaking, there are many forms of progression. Making you grind out ranks to give the sense of progression is simply the most obvious one, and the cheapest.