While I love this game, it is by far the worst game I have ever played for game breaking issues. While I realize the game is large and there's lots of ways to play, there are just too many things utterly broken.

Preston is unusable in my current game and I'm looking to see what other regions and individuals I need to avoid so I don't cripple my game further. I've submitted several bugs and tech support requests since the game was released and not received a single response. This is very disappointing. At any rate, is there some place where all the bugs have been compiled?

This should help

http://www.gamesas.com/topic/1544248-bug-report-index-pc/
for bugs

http://fallout.wikia.com/wiki/Fallout_4_exploits
for exploits

If you play on pc you could try to get the console up, click preston, type Disable, DONT CLICK ANYWHERE, then type Enable this sometimes resets the AI to the point where the NPC works again