Need a judge input to clarify what if any special powers (such as BCF or RCE) can be used to destroy walls or blocking terrain.

Destroying blocking terrian improved movement is the only sp that can destroy walls without having 3 or more printed damage.

This is incorrect. There are a lot of Special Powers and Traits that can automatically destroy walls.

As for the OPs question yes you can use BCF to try and roll a 3 or higher to destroy a wall/blocking terrain. Basically anything that let's tie damage go to 3 or higher could potentially be used.

For a list of those is suggest the strategy section of this website not the rules

I thought this got overturned with the overturn of being able to attempt to roll a critical hit when you had 2 damage.

No. The attempt to roll a critical hit was the only thing that was changed. You can still can still attempt to roll a 3 or higher with B/C/F to destroy a wall. It's on page 2 of Section 2 of the Player's Guide.

In fact, this subject was asked to be ruled on at Origins during a Battle Royale I participated in.

It's always been my understanding that basically any way a character can dish out 3 damage is good enough to smash a wall/object/blocking terrain. RCE, a good B/C/F roll, an object held with Super Strength, a Perplexed-up Damage Value, etc.

You'd be mistaken.

RCE says, "It makes a ranged combat attack against a single target character;"

Anytime a power states it targets a character than it only works on a targeted character. RCE, CCE, Energy Explosion, and Quake only affect characters so could not be used to destroy walls or blocking terrain.

Contrast with Flurry, which states, "Give this character a close combat action. After the close-combat action resolves, it may make a second close-combat attack as a free action."

Notice it does not say "...targeting a character..." so you could use Flurry to destroy an object or adjacent wall or blocking terrain.

Not Ranged (or Close) Combat Expert. RCE and CCE both specify you attack a single target character. You can't use those powers to destroy walls/blocking/objects.

Thanks for the clarification!

Did they change super strength to no longer give bonus damage vs blocking?

Yep. It was changed on the 2013 PAC when they made it so you can choose to drop a held object.

2012 PAC:
2013 (and 2014) PAC: