Perhaps, but you gotta admit, what else would be that powerful? This is technology that plowed through Federation, Klingon, and possibly also Romulan ships like they were tinfoil. And who else did that but the Borg?
Thing is, since we did not see Narada up against 24th century ships in the movie, we have no idea how it would stand up against them. Presumably Nero's upgrades would have given Narada the tactical advantage over them, but we have no idea if he could tear them apart as easily as he did the 23rd century ships.
I thought we were supposed to take from the context of the movie that Narada is so strong because its from THE FUTURE and umm, a mining vessel intended to crack large chunks of space rock apart and process it.
It should be obvious that Nero would have had to upgrade Narada. Remember, it was not his intention to go back in time, that happened accidentally. Therefore, if he intended to attack the 24th century Federation, he'd need something a hell of a lot more impressive than a "simple mining vessel" to get past the 24th century Starfleet. Therefore he'd have to upgrade.