I believe that he can be, yeah. Roger may have been the peak of strength at his time, but he was still relative to the other top tiers.
I think Roger gets a bit too much credit from us readers. Don't take me wrong, I don't mean to diminish his strength or being the Pirate King, what I mean is that the "legends of the past" in every series, be it here, Naruto or the Lord of the Rings, always cast a shadow over current characters due to their exploits and also by comparison to characters like Kaido who hadn't reached his own peak back then.
Zoro has already tapped into aCoC and will continue to grow exponentially, this is a very streamlined shonen, so even without getting into the whole "Roger was a swordsman" topic, I think Zoro can very well reach and surpass that level. Luffy will simply reach further than that in one way or another.