I know Bay's said it's not a reboot, but with every character completely redesigned, and with some character's apparently not even present in the new film, it seems to be a reboot to me.
Looks like it'll be a soft reboot, with the continuity being technically the same, but not actually connected with the previous films.
A reboot is "The Amazing Spider-Man" compared to the Spider-Man trilogy. TF4 takes place after TF3 in the same universe, hence no reboot.
It could be another one of those not-a-reboot reboots. We saw it with GI Joe where they kept some elements people seemed to like such as Byung-hun Lee playing the role of Storm Shadow but the costumes completely change and characters people didn't seem to like just dropped off the face of the planet. Or how Star Trek can say they are the same continuity even while changing everything and making a universe with two Spocks. With the way Hollywood is so paranoid about missing any ticket sells they will do all sorts of things to try to please everyone at the same time. Well except try to please Decepticon fans
I think it's in continuity but the story and dialogue will be much different than what we've seen before. I think it'll be a little more serious with no crude humor and character based maybe.
Will be difficult to judge - but unless they honestly state 'this happened in the last movie and our characters got here via doing stuff' then I wont accept it. It needs to link itself with the previous film. The same transformers doesn't count - as they are essentially large set pieces.
This. Also, the redesign could just be the characters scanning new modes and gaining new robot bits because of that.
Same continuity, the story has just moved on. It's not much different than when the G1 cartoon jumped twenty years into the future for the 1986 animated movie.