I'm the one who worked on those "improvements" Andy mentions, that will be in 2.5.2.
So naturally I'd be interested to make sure these improvements would actually fix the problems you are having. Would you mind sharing the project you are having so much trouble importing?
If it isn't possible to post it in a public forum, maybe you could send it to me privately (email@example.com). I won't share it with anyone, just use it to test / debug the importing of projects into STS.
Kris De Volder -- SpringSource