I think largely, yes.
Certainly supporting cast and rogues gallery should always be a priority for ever writer on every book. With Iron Man it's particularly important because both aspects are in need of an overhaul. I reacted poorly to Spymaster being identified as B-list but that's just me. For some odd reason, probably indefensible, I have always considered Spymaster to be a top rogue for Tony.
Making Tony uncomfortable is necessary, I guess, though I wouldn't have phrased it like that. He needs to be placed in situations where he's really in trouble. He needs to experience real fear.
Certainly the artist must always be top notch and must be well suited to the stories Slott wants to tell.
The "one big story" precept is probably a good one but I approach it with caution. Superior Spider-Man was a story I refused to read. There are Iron Man stories I will refuse to read, for example Tony going on a drunken bender, or Tony being corrupted by some unscrupulous super-model type, or Tony deciding he should assume control of western civilization.
The line that struck me was this, "iconic villains like The Mandarin are in desperate need of a defining story."
I think that's true. He's had good stories, like the Knauf's story, but he hasn't had a defining one. The closest was the Stan Lee orgin story, and that was five pages long. It's a really good five pages, combining the angst of tormented aristocratic children like Roman Sionis, tormented super-soldiers like X-23, and the disturbing exploitation of explorers like Christopher Columbus. That's really impressive looking back from the era of decompression. But it's still just five pages.