Just curious, is/was there or could there be this kind of ability where you go behind blocking or into hindering and when you come out you can perform a roll to move behind your opponent to perform a sneak attack for extra damage or some orher kind of bonus?

Especially if you are stealth andyour opponent cant see you. I know this is not Dungeons & Dragons but the thought just ocurred to me.

Do maybe Hand Ninja have this?

The Ambush feat allows a character with stealth to add +2 to it's attack when doing a close combat attack while in hindering terrain. The down side is when you use it, you lose your stealth for the turn.

I was told my my judge that Nightcrawler would not lose his stealth while using this feat because he does not actually posses stealth. Is this true?

Unfortunately it's true.
Originally using a Feat required possession of power, but (IIRC) when the Fantastic Four starter came out they changed it so just being able to use the power was suitable for the prerequisite. As Nightcrawler doesn't possess Stealth, there's nothing to be countered.
Also nasty with the Skrull Ms. Marvel

Pieces don't really have a back in this game. Not like Mage Knight had anyway.

there was a type back stab attack in mage knight.

Yep. Its why Feats are so awesome. Having the option to add a little comic-accuracy or improve upon "game design's" mistake is just genius. Well, I guess "was" genius.

Now WK/NECA have so many issues with their Special Power Feats, I can see why they stepped back from making any more of their own Optional Feats. Honestly, if they never changed the rules to allow Special Power Feats to act as prerequisites for Optional Feats they never would have had any issues.

Oh well, they can barely keep up with the Alternate Team Abilities and Maps so I can't fault them too much.

As a relatively inexperienced player, I like the Modern Age format. Then again, PrintandPLay makes playing Golden Age a nightmare sometimes. I remember when I first started playing it seemed like every team was using Protected, ICWO, Arp, Warbound, etc. It can be very discouraging for a new playing that's just trying to learn the basics. Such is life.

We did a mod once where backstabbing gave a bonus. It was defined as an attack from any square that could be touched by a line going from the center of the target square to the center of any square in the target's starting area.

The mechanic does not exist (other than the aforementioned Ambush) but I wouldn't be surprised to see a SP or Trait someday soon.

As opposed to only those Min/Max players that were able to prize shark multiple events or those that had the cash to purchase them at overly inflated prices?

I'm still pretty new and have seen that term before, "MIN/MAX." Can someone fill me in on what that is?
thanks

MINimum points/MAXimum benefit.

Basically making a team as efficient as possible.

Min/Max is a player that only cares about the highly competitive pieces and uses everything in extremes. They go for the best possible pieces, with the best possible feats to give themselves the biggest competitive advantage, no matter what.

Mostly, people here refer to it as cheese.

I guess that Ambush then answers my question. Because once you attack now everyone knows about you, so yea you wouldn't be stealthed. That just makes sense.