My idea is to make a simple to design and play game of superhero combat.  At this point I am not considering non-combat abilities - just fighting.  The idea is a game where you can make an interesting character in a few minutes and start having fun with super fights.

My goal is not to provide all possible powers from comic books, but to provide the basic effects that are common in comic books.  It is a minimalist system that you can use to make spiderman, superman, wonderwoman, etc - but not Dr. Strange or the like.

I am thinking of doing a dice pool system.  I like that because it is simple to play and makes buying abilities simple - you buy dice and that determines how effective it is at something.  You roll your dice (d6) and each roll of a 4+ is a success.

This is an attributeless system.  Characters just have powers.  Each power is bought individually and is balanced individually.  A character has 12 points to spend per power.  For 1 pt they can buy 1d of to hit, 1d of damage, buy 2 squares of range, 1 radius AoE, etc.

So a character can have a Punch attack which is 6d to hit and 6d damage.  And they can buy a Haymaker attack which is 2d to hit and 10d damage.  Or they can buy a Throw Rock attack which is 4d to hit, 6d damage with a range of 4 squares.

Each turn the character determines which power they use.  Having a variety of powers gives you flexibility to deal with your foes.  Against a bunch of weaker foes an AoE attack is useful, against a slow but tough foe a high damage attack is useful.

For defenses characters get 8 points.  Each point buys 1d of defense (avoiding to hit) or 1d of resistance (avoiding damage).  You get fewer defense points as attack points because you need both to hit and damage to succeed to hurt someone.

Attacker rolls to hit dice, defender rolls defense dies, if the attacker gets at least 1 more success than the defender, they hit.  Attacker rolls damage dice, defender rolls resistance dice, for every success the attacker gets over the defender they inflict 1 point of damage.

Example: attacker has 6d to hit, 6d damage.  Defender has 4d defense, 2d resistance
Attacker gets 4 successes to hit, defender gets 1 defense success - attack hits
Attacker gets 3 successes on damage, defender gets 0 resistance successes - attack does 3 damage

in addition to doing damage there would be:
debuffs - reducing your foes to hit, damage, defense, or resistance.
buffs - increasing your or your allies to hit, damage, defense, or resistance
healing - restoring your or your allies lost hit points

looking for feedback
- are there simple superhero games out there I should look at?
- dice pool games I should look at?

I think your problem here is that the environment needs to change in order for the attacks to change.

Your players WILL find the most optimal attack type and just keep 'spamming' that one, which seems the thing you don't like.

The only thing that would change that is a change of environment/change the opponents - which so far, you've written nothing about. So while your attack system seems complex, it will boil down to something very simple and the same attack over and over again, as it stands.

What I'd suggest, before trying to both make a point buy AND a variable environment at the same time, is to consider stuff like cooldowns. Like say you've used an area of effect - that option goes on cooldown. Either you can't use it for X turns, or you can, but it costs double the amount or such.

With powers going on cooldown, it'll ensure the same attacks aren't repeated over and over.

1. Yes, changing environment is part of it.  One of the ideas is that the foes could be very different.  So within a fight you might not use a variety of powers, but over multiple encounters you would

2. I am considering cooldowns.  You can add limitations to your powers to get extra points.  I might just go with usable once per encounter, and takes 1 round to recharge.  I am also considering takes an action to recharge it.

because the damage system is subtracting resistance, attacking twice with the same damage is not as effective generally as attacking once with a more powerful attack.  So taking an action to increase your damage on your next attack would be useful against tough foes.

1. Yes, changing environment is part of it.  One of the ideas is that the foes could be very different.  So within a fight you might not use a variety of powers, but over multiple encounters you would

Apart from Callan's points (which I think are spot-on), you might want to consider making defenses static values instead of rated by dice. This will reduce the rolls to half the number, which should speed up play and help keep the action going at a fast and furious pace.

However, this will also affect the potential outcomes. With static values it will be impossible for someone with only low-damage attacks to injure someone with high Resistance, which may or may not be what you want. Should a fairly weak punch be able to affect Superman or the Hulk? I could see going either way, but I think it's something to consider.

In any case, the basic idea seems workable.

static vs fixed defenses were a big concern of mine for just the reasons you outlined.

the trouble is that I want you to be able to min/max defenses - it's how comics work.  The Thing doesn't dodge attacks, he just gets hit and can take it.  Whereas Flash dodges all attacks, he isn't tough.  Having characters with min/maxed defenses makes it much more likely that lower powered characters will not be able to affect them. 

When I get to playtesting I imagine I can change it if the extra dice rolling drags things down too much.

Some playtesting will probably tell you how you want to do it. I look forward to hearing how that goes!