Interesting post. So you are saying that the three sat characters are in fact as fleshed out and useful as the solid one and two stars?
Some, but not all. Rags and Mags are #1 and 2 in this game.
The misleading thing is that at the same level 2-stars are better than 3-stars. i.e. lvl 85 Thor is still better than lvl 85 IM40. It's not until around lvl 100 (maybe about 30k ISO investment) where IM40 starts to get good. But IM40 goes up to lvl141, so it's a long-term investment. Rags and Doom are more economical because they both cap at lvl115.
Ordered roughly from best-to-worst IMO.
Rags gets 660 dmg with 2 red AP; Thor gets 1100 dmg with 6 AP. Rags has 7k health; Thor, 5k. They're very similar characters, but pound for pound, Rags just overpowers him.
Mags is the best single target dmg dealer in the game. He can 1-shot KO Rags' 7k health with Magnetic Translocation, 10 purple AP.
Spidey is useful as the best healer in the game. Not gamebreaking, but you'll never need to use packs again. I'm sitting on over 100+. Plus side is as a support character, you don't need to max lvl141 for him to be effective.
IM40 isn't as good as the above, but he makes a decent tank with the highest health in the game and synergizes well with Thor, Wolvie, Spidey etc.
Doom is pretty good. Once maxed, his Summon Demons do 1100 dmg per turn. So after 5 turns of just tile-matching, most characters will be dead. However, I would say he supplements the main damage dealer on the team, not replaces them. So Thor+Doom, Rags+Doom, Wolvie+Doom, etc.
g.Widow has the best AOE in the game. 3k dmg to each for 19 green AP. Very deadly but the expensive costs make her a liability. If you want the fastest wins in the shortest amount of time, Rags+g.Widow is one way to do it.
Hood is a good support character. His passive steals 1-3 AP every turn for free. It's not just about gaining AP for offensive use, but also AP denial defensively. But his low damage and low health make him a liability. He has lower health than many 2-stars even.
Loki is pretty much a solution to a problem that doesn't yet exist. He is a hard counter to teams that rely on strike/protect tiles, but they aren't common enough in the meta to warrant his use. Spidey was given protect tiles in a recent buff and Punisher just got released, so we'll see how it changes.
Regarding Daken vs Wolvie. Daken caps @ lvl69, Wolvie @ lvl 85. Those levels make a difference. Off the top of my head, it's somewhere around an extra 1k health, 40 damage per strike tile, an extra 50 heal per turn. It adds up over time. Daken is still very useful though because his strike tiles are free and has good colour selection.