The XL5F and the XL7F are both towers -- nearly the same size physically, both 3-way systems. And the frequency response chart for the XL5F as presented by Fluance isn't as flat as your top chart, but isn't as jagged or discontinuous as your bottom chart either. Is your XL7F chart from before Fluance fixed the crossover problem in that model?
What frequency response charts don't show you is how far the speakers go into fine detail. What I've realized comparing the XL5F's to my Klipsch RB-51 II's is that although the Klipsches have beautiful tone, they hollow out the sounds compared to the Fluances. That is, they leave out a lot of the subtleties of the harmonics to present a cleaner, in some ways prettier tone -- but one without the fuller presence of the voice or instrument that the Fluances present.
I'm not dissing the Philharmonic, which I've never heard. And no doubt the XL5F's are so deeply discounted because the market hasn't taken to them. But they've improved my system way beyond $200 (which when in 7.1 mode has the Klipsches as DSX highs, Polk center and surrounds, and a BIC subwoofer -- all of which blend quite well for most stuff, although for raw blues the XL5F's are best by themselves -- and far, far better than the Klipsches alone).