I'm a well read grad student who's bluntly honest about all things, although I try to be most honest about myself.
Marvel, DC, most companies that own multiple franchises that can easily be sucked into a crossover do this occasionally. They want people to buy titles they normally don't, because they feel like they need the whole story. If anything, the Black Vortex crossover proves that you do need everything to really understand the whole story.
Unluckily for Marvel, I am not easily blackmailed into buying books I'm not interested in. I do have the Nova Black Vortex somewhere in my Comixology but only because I really ended up liking the Nova series.
Also, for everyone getting into Marvel comics, beware. Earth-616 is going away. (For those curious, but who aren't into Marvel continuities, they number them. Earth-616 is the 'normal' Marvel Universe, the Ultimate universe is another number, and so on and so forth. So pretty much they're rebooting everything. Kinda. The Ultimate-verse may or may not have been eaten by Galactus in another series I don't follow, although at one point I heard a rumor that Ultimate and regular Marvel-verse were going to... blend.)
New series. This is the end of Legendary Star-Lord, as he reboots his series with Kitty Pryde. (The Legendary Star-Lord and Kitty Pryde series may or not may be an ongoing; I've heard other rumors that this might be a whole new Secret Wars thing, and that this might be a mini-series during Secret Wars and then there'll be a whole new series.)
Sound frustrating? It all kind of is. Especially as I was liking the series as were. I'm sure the Groot series will be amazing, but I'll miss the Rocket series. Anyway, I was irked enough by missing parts of this story - and no, thank you, I still don't want to be forced into series that I'm not interested in - that I knocked down one star.
That being said, it was fairly easy to follow this given the missing comics. And I really did quite enjoy the characterization and even the plotting in the crossover. It was a ginormous space romp with a lot of heart, humor and action.
If only it weren't also a clusterfuck of a crossover that demanded I spend money on titles I weren't interested in. (Yes, this is a major pet peeve of mine in comics.)
Sighs. I'll miss this title. Here's to the next one being just as good!