I didn't feel guilty... I expected better of him, im the one that basically saved his town and housecarl from becoming dragon lunch, im the one that storted out his son ( sorta )
he knew i was a stormcloak when i delivered Ulfrics axe, yet he still made the wrong move based on his personal dislike for Ulfric.
I didn't feel guilty either, and in fact considered Balgruuf's comments to be a cheap shot based on his apparently having assumed that because I helped Whiterun earlier, I couldn't
possibly have a different view of the overall situation than he does. It was almost as if whoever wrote that particular bit of dialogue based it on his/her opinion rather than the one Balgruuf is supposed to have, which is a
major sin in script writing; you
always write from the point of view of the character, not the author, since the whole point is to have the character respond the way he or she is meant to.
During the axe exchange itself, I felt there was a big missed opportunity given the fact that Balgruuf is currently fence-sitting. When you give him the axe he does not immediately respond, but since you don't get to say anything about why it was given you can't convince him to back your side and avoid a needless battle. If they had given you that opportunity, they could have then run with it and let you use the fact you'd swayed him over as a means to (at least try to) influence the Jarls that are more firmly opposed to you to come over as well. Obviously some would refuse, for various reasons, so you'd have to fight no matter what in the long run, but at least you could try to minimize the slaughter.