Edit: Fixed some numbers because of cards pointed out by commenters where timing doesn't quite work. Updated with a new heroes up through War Machine.
This is the strongest, though most restrictive, non-hero resource generator we've seen yet due to is low cost of only 1 resource. All current Superpower cards are hero cards (except Invulnerability, which is horrible), so you can't actually build a deck around Deft Focus, but some heroes will benefit from it more than others. When evaluating this, consider it takes 2 uses to come out even on resources, and 3 to come out ahead.
Here is a list of heroes ranked by how many of their cards can take advantage of Deft Focus. Obviously, this excludes cards like Fruition or Speed of Light that are Superpowers but zero cost. Some superpowers that are interrupts during the villain phase are also not counted since Deft Focus is used as an action, not a resource.
Tier 1: close to an auto-include
Quicksilver (13), Groot (12), Spider-Woman (9), Spectrum (8), Adam Warlock (7)
- Deft Focus is amazing with these heroes simply due to how many Superpower cards they have. I would always play 1 and consider playing 2.
Tier 2: warrants consideration
Hulk (6), She-Hulk (5), Scarlet Witch (4), Thor (5), Spider-Man (3), Captain Marvel (5), Ms. Marvel (5), Iron-Man (3)
- While these counts may be low, remember it only takes 2 uses of Deft Focus to break even. I would think about playing either 0 or 1.
Hope you like my breakdown, and let me know if you've tried it and found success, especially with the Tier 2 heroes!