If she got a good fruit, then maybe. Otherwise not so much. The rest of the crew had a destiny called Kuma on their side, sending them to highly beneficial if not necessarily nice places for very special training. I'm sure Vivi has been training all this time, but it has no doubt been training to be the next ruler of the country. Not to mention as essential, if not more so, have been the continuous life and death experiences the crew has gone through since, plus all sorts of potentially less dangerous but still exceptionally enlightening encounters and discoveries.
Nami isn't that weak anymore. Sure, compared to the real powerhouses, but she can take care of herself. She's vital as the navigator in any case, so even if the others have to dedicate effort to ensuring her safety, it's still very much worth it objectively as well. Vivi, however, wouldn't have a special role in that sense.
I liked Vivi's character back then. She also reduced the sausage fest factor, but this isn't any place for her anymore. Maybe it wouldn't be so bad if Straw Hats did have a cute female member, like Koala, for example. Nami's looks are certainly cute, but she has quite an ugly personality.