I personally don't feel that intellectual capacity is the only characteristic that can elevate (or differentiate) a character over just someone wearing the suit.
For example,I feel that Frank Castle makes for an absolutely ruthless Warmachine because of his single mimded focus and ruthlessness.
RIRI never impressed, me. Her intelligence just make her come of as a female tony stark clone to me. She fits right in with Marvels agenda to supplant it's powerful male archetypes with female versions.
Rhodey was always interesting to me. While he lacked Stark's genius, he exhibited a certain level of resourcefulness,aggression and stubbornness that made him unique. I loved his first encounter with the Mandarin.
Agreed, Rhodes proof that resourcefulness is not something reliant on engineering know how.