You could think that, but like I said, based on my experience with BF2, it works.
There, the senior ranked players had first choice of whether or not they wanted to be the commander. Everyone puts in their bid blind, and it choose the highest rank among the bidders.
So you'd think you'd never get to be commander. But as you get up in levels, higher ranks started getting rarer and rarer. And some people just didn't want commander to begin with.
Hopefully it just doesn't automatically make the highest ranked person the hero. Looking visually distinct, that'd probably be something people would want to be able to opt out of. Maybe there's different heroes per class, meaning a bunch of people get the chance to be heroes per match, and not just the two highest ranked people.
There's also something called a battlefield commendation (or promotion), which is basically a temporary rank up you earn in a match for exceptional performance. That might get some people to the hero level when they might not have otherwise.
There will always be limitations in RO though. RO: Ostfront has limits on class types, with snipers at a default of 1 per team. That's just something you have to accept with TWI games, they don't want games where everyone is lopsidedly picking one class. Likewise, they want veteran players to reap the benefits of their time. Heroes should be the goal for all players, but not all players should get to be heroes all the time. I really think, despite how much heroes seem they're going to get, that they're going to be a minor part of the game by and large. Depending on when people become heroes, no one might even see them for a month or more. (Doubt it, but you never know.)
Once you've got the rank, you can just hop on to any server and probably have a good chance of being the hero. We like to think FPS populations all rank up together....but playing BC2, I see newbies every single day. Hopefully ROHOS does well enough it doesn't get stuck with an uber veteran population, and the occasional poor sucker just trying the game....as RO: Ostfront has kind of become.