You said I did not answer all your points. In the interest of being completely engenuous here you go....
They attack ridiculously fast
WAI. Their current speed is not a bug. It is intended. That's not to say they might alter the speeds slightly as they continue to develop but MM and faatal have both stated the zombie vulture speed is working the way they intended.
they can share space with other vultures
8 clawed megavulture clump ( I really think TFP needs to either implement proper collision for their mobs or balance everything around them being able to exist in the same physical space)
This could be a bug. Get a video showing vultures clipping into each other and merging together and post it in the bug forum.
Vultures now guarantee infection
Not true. I've been hit and not infected. It is a very high chance though and after the first hit if you are hit again the chance increases so making sure you don't get hit more than once is important to avoiding infection.
riding bicycles a frustrating slog
WAI Bicycles are best for the forest and snow biomes. There is zero slog for pedal bikes in those two biomes.
You usually get a bicycle when you are still pretty fresh in the game and the tougher biomes are going to take some extra skill and work to enter if you insist on doing so with a pedal bike. Vultures are faster than the bicycle so you can expect to be dismounting often and killing vultures. Or you can run on foot in the tougher biomes and not be bothered one bit. Once you get a motorized vehicle then it is easier to stay ahead of the vultures. You will still need to jump off and kill them but it is much less slog than a pedal bike.
In the early game when antibiotics are very difficult to come by, vultures basically create a frustrating loop of infection deaths that sucks all the fun out of the game.
WAI for those who do not respect the location based difficulty mechanics that are now being developed for the game. It was the same back when we had the huge city at the origin of the map. People would spawn in naked on Day 1 and run repeatedly into the city and die and then complain about the same kind of frustrating death loop. If you want to challenge yourself and test your skills then bike into the wasteland or burnt forest or desert repeatedly before you are prepared for it. But if you don't want that challenge then stop doing the behavior that brings it on. This is the issue with location based difficulty. Some players think they can just go anywhere they want since it isn't gated off. It is an open world. You are supposed to learn after the first time riding your bike into the wasteland not to do that any more. You aren't supposed to keep attempting it over and over and over again if it is too much to handle at your character's stage of progression.
This is before you take into account all the other new health conditions they give you (how exactly does a vulture break your leg? Beats me, but it happens all the time). Generally, an attack from just one vulture generally leaves me with infections, concussions (did it fall on my head?), abrasions, and sometimes the aforementioned broken leg, even though I'm wearing heavy armor.
WIP... The new critical injuries are brand new and completely random. So yes you can currently get some that don't make sense for the situation. That will be refined as they add additional injuries and can hopefully differentiate which injuries are possible given a situation. For now, they want us to test and experience all the injuries. The more you get hit the higher percent chance you get to receive a critical injury of some kind. So if you are getting hit a lot then you could certainly end up with a long list of injuries you need to fix.
Don't get me wrong, I like the new health conditions for the most part, but I have used at least twenty antibiotics in the first seven days, which is nuts. I just cheat them in now whenever a vulture attacks. I really don't see new players enjoying this at all, since infection is the one mechanic that relies entirely on RNG early game. A new player can make splints or bandages, and pain killers are fairly plentiful, but antibiotics are incredibly rare in the early game.
WAI based upon the design that players will learn. You aren't learning. You stubbornly insist on riding your bike through tougher biomes. New players who stick to the forest or snow when on a bike and stay on foot other places won't be dealing with any of that. Everyone has fun their own way. Some will find it rewarding to level up and eventually become strong enough and have a vehicle fast enough to cruise through the tougher biomes with just a few big vulture battles and plenty of remedies to fix the resultant injuries. You find it fun to go into tougher biomes before you are ready and then cheat in remedies for yourself. <shrug> To each their own.
Dying through your own choices with an occasional RNG death is reasonable and entertaining. Being stuck in an endless death spiral due to infections you have no control over leads to uninstalls and refund requests, which would be a shame. I love 7D2D but that is partly because I know how to edit the data files.
You ARE dying because of your own choice. There will be some players who quit and uninstall. There will be some players who figure out they should remain in safer zones until they are ready. There will be some who intentionally enter unsafe zones early on for the challenge. There will be some who cheat in gear and remedies to compensate for their inability to survive in tougher areas before they are ready. There will be some who mod the files so they can do whatever they want whenever they want without any risks or threats. All are valid ways to play your own game in a way you like. But the idea that some players will quit is not a valid reason for the developers to abandon location based difficulty-- at least I hope they won't ever listen to that.