Yaarel
🇮🇱 🇺🇦 He-Mage
The superhero characters are for inspiration, to build 5e versions of them. These would be high level D&D 5e characters with the 5e gaming engine and 5e mechanics.Having actually played marvel superheroes before I can say it's so different from d&d that it makes any comparisons rather questionable at best.
A main difference between 5e and the superhero genre is, 5e magic tends toward neovancian spell slots whereas superhero powers tend to be always-on. But there are ways that 5e can accomplish always.
Cantrips are always-on, albeit they tend to be minimally powerful.
Allowing a Fighter to substitute the Weapon damage types (Pierce, Slash, Bludgeon) with other damage types like Fire and Psychic, is an effective and balanced way to establish always-on superhero flavor.
A spell itself can be always-on. Compare the Mage Armor spell whose duration is so many hours, on is moreorless swapping a spell slot for an always on power. More spells can be like this, and at higher levels. There can even be a new spell mechanic, where the spell "occupies" a spell slot. In other words, as long as the spell effect is on, the spell slot cannot be used for anything else.
In any case, I feel these always-on spells are vital to design for the sake of the 5e game. These kinds of spells would be in normal spell lists, and they would compete with more traditional one-off vancian spells. It becomes easier to assess how powerful the always-on spells are compared to the one-off spells. This link, makes it far more easier to balance spellcasters with Fighters whose powers tends to be always on.
It is too bad the short-rest Warlock is retiring. It would be so much better if every spellcaster switches to short-rest refreshes. Short-rest is so much easier to balance because there are smaller amounts of magical resources at any one time. To go nova is less of a balance issue. The short rest is truly ideal for satisfying amounts of magical flexibility and intuitive usage, while also maintaining gaming balance.