Not really, considering that Feige has repeatedly talked about how they're not opting for a darker direction in the Marvel Cinematic Universe and Venom, well, IS a pretty dark character.
Frankly, I don't know how they're going to handle his origins without Spider-Man, but I'm more excited about Tom Hardy starring in a Ruben Fleischer-directed Venom movie which can delve deep into the characters' heart and horror.
I'm pretty excited by the idea of Hardy playing Brock in a movie which won't tone the character down. Sony has managed to bring a spectacular actor on board to play the character, so they must be doing something right. But hey, what do I know... Warner Bros., Fox, Sony and pretty much every studio which isn't under Kevin Feige's supervision sucks, right?
In in the best-case scenario, maybe Venom will fight Spidey in later films - who knows...
I'm sure Marvel Studios and Sony Pictures agreed on which characters the latter could explore on their own VS the ones which Marvel would like to use in the MCU. And if Feige & Co. aren't interested in Venom, why should Sony just let him rot if they can make a movie? Especially one which is starting to seem pretty promising and interesting. And don't get me wrong, I don't hate Marvel Studios. I actually don't hate any studio. But they're not exactly movie paradise like people around here claim. Their movies seem as hit and miss to me as anyone elses' (for example "Doctor Strange" was pretty forgettable and bland IMO, while I thought "Guardians of the Galaxy Vol. 2" was great).
The trickiest part of doing him solo is his origins. Other than that the character has had his own series in comics, so it's not like they've decided to make a Mysterio movie without Spider-Man.