Ant man is a founding member of The Avengers and the creator of the villain in the second Avengers movies,I would hardly call him loosely connected. Also it has a great director in charge so I would say we are in safe hands.
Oh and as I said I know nothing about them but I applaud marvel for taking a chance on GOTG. Most studios wouldn't give something that off beat a chance. I am glad they are using the success of the other movies as a spring board to try other things and hopefully GOTG will do well so they will give other lesser known comics a chances. Projects like Ant Man and GOTG give me hope that Marvel is willing to shake things up and will not let this universe go stale an time soon. I hope the rumors of a Doctor Strange movie are true because I would love to see that and it would really shake things up.