So far I've been having a blast playing this game in PC co-op with a friend of mine. She has played Caddoc exclusively whereas I've played E'lara exclusively.

While it took a little while to get used to using one button for cover, vault, and sprint, the only real difficulty that I'm having now is with running. For some strange reason, when holding her bow instead of a blade E'lara will only run in straight lines — she cannot turn.

This is not only annoying, but it seems highly arbitrary and illogical considering what an expert she is with ranged weaponry. Being as I practice archey and swordplay myself, I'm hard-pressed to think of a reason why a character should be able to execute a diving roll with bow or blade in-hand yet not be able to avoid running into a wall. After all, she can turn just fine while sprinting if holding a sword.

Is there some work-around to this behavior, and does it exist on other versions of the game as well?

Afraid you'll have to live with it. I'm guessing the developers wanted ranged combat to feel more like Gears of War where you can't really maneuver much while sprinting. Otherwise, why would you ever want to do anything but sprint? It's good enough for sprinting from cover to cover, which is what you'll mostly be doing. Then I'm guessing they realized melee combat will be about sprinting towards enemies more, and let us maneuver a little more whilst doing so.

Personally, I agree with you. I think it Caddoc's turning penalty whilst sprinting is high enough that it can be applied to E'lara too. It's just annoying having to select melee weapons every time you're outside combat and want to keep up with Caddoc who's sprinting to the next location. Even in combat you sometimes might be evaluating whether you should select your sword before starting the sprint, then reverting back to your bow once you're behind cover. I don't like how the game encourages corky gameplay like that.

It makes good sense though.

The faster you run, the less you can turn while doing so.

I think it works as it should in the game.