Doomguide nailed it. Aim gives you more control over it, while Tactics triggers more often in teams. That depends on your playstyle.
It only has 3 FF powers because the other 6 do things few people need or want done. They either protect enemies from your team by knocking them out of reach of your AOE or trick you into wasting your turn by inflicting less damage than your real attacks. The three good powers only need to be cast once every 240 seconds to protect your team with ~36% added defense, giving you more time to blast enemies or throw sharks at them.
Sure, here's a basic armored build for you. Soft cap positional defenses, hard cap SL resistance. AOE KB mitigated to place nice with others. Two periodic heals, okay end recovery.
Here's a classic Superman build, complete with heat vision. Defenses are shown with one enemy in melee range. A second enemy or a team mate with Maneuvers gets you soft capped defense to everything but psionics. Resistances are good with one stack of the tanker ATO.
It gives benchmarks for each level of every power, plus a dozen heroes to weigh a new character against. If the player is familiar with existing Marvel characters, it should be easy to estimate where your new hero fits. That's more player-friendly than systems with strict limits. "I know you wanted to play a scrapper as nimble as Spider-Man, but you don't have enough points/didn't roll high enough, maybe one day you'll get there." It would be swell if it included archetypes or classes or similar structure for players, like you find in GURPS Supers and M&M. But it is entirely possible to generate a character with MHR rather than play an existing hero.
Or you could use the character modeling guidance that the book tells you to use. FASERIP had modelling, but that was largely reserved for published comic characters. MHR was the first system one I know of that encouraged players to start the game with the character they want to play, instead of hoping for lucky rolls and quick levelling.
I started with Marvel/FASERIP, grabbed SAGA and MHR, tried Heroes Limited from Palladium and Mutants and Masterminds 2e. Read DC Heroes and Champions, didn't work for me. I barely give the edge to MHR because I don't need to futz with NPC intelligence or subtle power levels. Inshallah the new Marvel game coming out in 2022 will be better.
Here's a quick backport from a Shield Dark tanker I had lying around. Took way too many attacks, but it should give you an idea to improve toughness. SL resist cap with one stack of ATO, okay heals from Fitness. Should probably drop some melee attacks to get a ranged one.
Why are keybinds for changing the power trays so popular?
Because forms have too many powers to fit on one tray, so you need a way to change your shape and tray at the same time.
Looks like the Blaster ATO, Winter O's, Kinetic Combat, and Thunderstrike. From memory: Winter O's boost end recovery, defense, and FC resistance; the ATO boosts recharge, hp, defense, resistance; KC boosts SL defense, Thunderstrike mostly boosts ranged defense.
Here is one direction to go. Elec is a resistance armor, with little if any DDR. This build gets you hard capped SLFCP resistance, while adding enough defense that you can reach soft cap melee defense with a small purple.
Mind control has a good ST attack chain, doesn't really bring AOE until the epic pools. I've heard it's better on dominators, if you can stand them, but Assault sets don't match your concept at all. Pain brings debuffs, heals, and resistance buffs; don't see a recharge buff.
Ill/Kin controller. They can cast invisibility to protect the babies or drop PA to diffuse threat. A sonic blast character would be good for bigger orange numbers, but would need more active use.
With the following binds, you hit one button to shift your form and tray for dwarf or nova. If you press it again, it shifts you back but not your tray. So I included another button that toggles on your basic shield and shifts your tray back to normal. Sometimes tray shifting chokes, or you don't want to wait, so you can put key human powers on your alt or control tray.
Like the others have said, Brutes have to rush from fight to fight to keep their damage up. Scrappers don't care if you have to AFK for a few minutes, they're ready to go as soon as you are.
This struggle is what drove the creation of Sentinels. As the others have said, use your controls. You can't one-shot mez a boss, but you could mez a minion while you go ham on the other. Chug inspirations, they're not just for decoration. I'm not sure if the KR arc made it off the Beta server on live, but it sounds like it was overtuned like they did with Praetoria. What is your primary and secondary?
Ageless, sure, but not Alpha. Toggle the different Tier 4s and notice how little they help compared to offense:
Agility Core +0.25 recovery, +2.5% def
Cardiac Core -0.35 end drain, +3% resist
Intuition Radial +16-30 feet, +32-90 damage
Musculature Radial +0.15 recovery, +32-90 damage