Look like Kurtzman finally got canned since he started sucking after he thought he was invincible post-Mission Impossible 3. The downside is that sony didn't know what do with with TASM3 and Venom without him. (And Venom Carnage is a terrible title.)
Sinister Six being a team-up film/reboot two years after the second film in a reboot franchise is also a terrible idea. It's rushing things way too much and having to reintroduce all sorts of familiar characters. That's insane and when Hollywood is already seeing reboot fatigue and superhero films that don't meet a certain standard of quality are also failing, the last thing an audience would want is a superhero reboot to be rushed out the door.
Marvel Studios may have only gotten to first base with Thor: The Dark world but they've been getting hits consistently. Fox got two strikes but then knocked it out of the ball park with First Class and they've scored ever since. Sony had their three strikes. They're out. Sell the rights back to Marvel. Have Marvel do a Spider-Man TV show that teams Spidey up with the Defenders and then call it a day.
And yes, this does mean that Marvel Studios should pay an absolutely crazy amount of money for Spider-Man back. Regardless of what the IP was worth in the early-mid 2000s, it's tarnished now. The reboot series has been getting diminishing returns and and TASM2 is regarded by most as another X-Men 3 which turned a massive profit but will hurt the franchise's box office numbers in the long run.
Keep in mind that while the X-Men franchise may have had two poorly received films in a row, Fox managed to bring the level of quality up with the next three to such an extent that it was able to rival, if not surpass what Marvel Studios was doing.
Launching Sinister Six with the Six as brand new characters and good guys, doing a new origin for Spider-Man and recasting everyone isn't risky, it's stupid and it's not going to be able to turn a profit. The rights should be sold back to Marvel. Let Marvel Studios give Sony a few hundred million for Spider-Man back, then reboot him on Netflix in the MCU.
And this is coming from somebody who's cautiously optimistic about the FF reboot.