I do think Elinor is more observant, and very witty. Elinor is definitely the one with the sense of humor in the family.

And yes, Marianne is completely wrapped up in herself- selfish and a bit of a know-it-all. I think perhaps those attributes while evident in her behavior in the novel are not listed in Austen's description of her. I think because of this, I attribute some of that to her immaturity, so well put by Outi in this thread (post titled "I understand it differently").

Where you say Marianne thinks Elinor's calmer nature means she's less feeling, I attribute this to Marianne's idea of sensibility. Stealing terms from others, Barbara in another thread described it as "prescribed reactions" and Elbe in this thread called it Marianne's "argument in life".

This idea is striking to me in this sentence
"Esteem him! Like him! Cold-hearted Elinor! Oh! worse than cold-hearted! Ashamed of being otherwise."

For Marianne there was a prescribed reaction and Elinor's description of her own feelings was not it.

Hopefully I'm not quoting people in ways they would not wish, but I have described how their words fit into my understanding of Marianne.