Personally I liked to see Ezekiel Stane appear in a future Iron Man movie. It's possibly that Obadiah Stane could have had a son in the MCU, so the idea of Ezekiel seeking revenge on Tony for his father's death could be interesting. They could even adapt Matt Fraction's The Five Nightmares storyline from Invincible Iron Man and adapt that into a film.
Yes and have Sasha Hammer as Ezekiel's Girlfriend and the daughter of the real Mandarin. The Mandarin then appears in Iron Man 5 coming after Tony for the death of his daughter (IM4) and most importantly the destruction of his reputation from IM3 (which he comes to blame Tony for).