I have to agree with
StW here, if we only judge which changes were good and/or worked and which didn't, then the change of Boromir's appearance indeed affected the film neither positively or negatively (at least he wore pants
). I believe the only reason for this change was to have even little children - and teens and adults with the attention span of little children - be able to distinguish Boromir and Aragorn.
I hate to say it, but making Boromir more likeable and identifiable with was probably a change to the better. Personally, I would have very much preferred Boromir as he should be.
The stairs scene on the other hand, yes, it was exciting to watch, but it made no sense - and not only once you start thinking about it afterwards, but right away when you watch it for the first time. And it took screen time away from things that
would have made sense, Gandalf's early confrontation with the balrog along with the destruction of the Chamber of Mazarbul, for example.