I think your first paragraph contradicts your second. It was self-defense under either version given the preceding conversation - which is what makes the whole character arc argument nonsense. I think the change is corny and unecessary if I focus on it, but the cheesy thinkg about it is the fact that Lucas felt he needed to make the change in first place, not what it really does to the film itself. And I just don't get the mantra that it fundamentally changes Han's character. There is nothing wrong with what he did in either version and I'm sure he would have done the same if the episode happened after the end of the third movie.
Also I don't think most people even notice the change if they don't know about it (I certainly didn't notice it when I saw the SE in theater). I didn't say, wow Han is a completely different guy in this version of the film. So the very fact that you have to be a pretty detail oriented fan to even notice it confirms to me that it really doesn't change Han's character at all. The whole debate turns on a rather obsessive point about logical consistency--and not the actual impression you get when watching the film without all the fan baggage. A bit ironic given that the SW films are not exactly the paragon of logical consistency.
In any case I agree with the initial point that these are perfectly fine in SE. It's nice to have the original versions so that what I saw as a kid is preserved, and some of the changes are annoying (although I would put the dance number in ROTJ some of the less subtle CGI stuff way up higher on the list than who shoots first), but the changes don't fundamentally affect the experience of the film for those who are not invested in this whole debate.