If you want to close the distance and work inside by bobbing and weaving, do you more or less have to be square? It seems like its much more natural to advance with your toes pointing forward and you shoulders more square. Of course I dont mean totally square, just led shoulder and hip slightly forward. Think Joe Frazier. I know that from a good slanted stance, it's difficult. Especially slipping/rolling left. Thoughts?
Not at all, be square if you want to put pressure on from both your right and left hand, otherwise weave and load up a side for more power when picking your shots, both can and need to be done if you know how, it sounds like your footwork or somthing is messing you up, watch what your feet and knees are doing and play around with their positioning until you can weave loading a side properly.
Sometimes it pays to watch people who are good at it, Mike Tyson for example. Compare him to Rocky Marciano who wasn't so good.