No.
Rihanna is turning into Westlife in term's of impact. Let me explain (to the OP).
Westlife where a boy band who had 14 number one's in there shortish career churned out one after the other, most of the later one's hyped by Simon Cowell TV programmes (they where on his label), and then disbanded with no musically legacy and the majority of people couldn't name five number one songs by them or actually care.
Unfortunately much as I think Rihanna is talented, this is the direction she has been pushed or decided go in-one song after another. If she prefer's this to releasing quality songs at a slower pace which will be remembered in 20, 30 years, then that's fine. That's not to say she hasn't done big tracks, she has, but musical trend's aside, Umbrella and one or two other's will stand the test of time-but there is a lot of unmemorable stuff as well..
Janet Jackson at least to me anyway, is a legend. Quality songs, amazing back catalogue.
Beyonce is good but apart from the stuff with Lady Gaga recently she' has offered anything that's interesting musically certainly with the last album.
Whitney Houston-when she was at the top of her game she was unreachable.Rihanna does not have that level of talent nor fame-it was a much more crowded music business in the late 80s/90s than now, huge competition from many more global star's.