and I feel like Elinor when I read this part.

The first time I read it, it had a really profound effect.

The endearing part is when Colonel Brandon confesses that;
".....and my affection for her, as we grew up, was such, as perhaps, judging from my present forlorn and cheerless gravity, you might think me incapable of having ever felt."

I think only Marianne felt that he was incapable of feeling so, or to be fair to her, she thinks he must have felt it, but was beyond it now - which I don't think he is.

Yes, it would have done Marianne good to hear it directly from him as one sees that it has brought some gentleness in her manner towards him.

His dilemma is genuine enough, I think.
A very very difficult decision with so many things going against it, and I think that by telling it he put Marianne first instead of himself, another big plus.