It could be either, though the former is far more likely to be the case. You should try to recognize the maximum distance that your 2A will hit, and try not to press it when they are either too far, or you feel like there is a frame trap coming (a frame trap is where the opponent does a series of moves that give you a small gap that you can attempt a 2A, but you will get hit if you try to do a non-invincible move). Checking out the revolver action (sometimes called gattlings on this site) is definitely a good idea though, even if it's not the reason your 2A is missing.
In Blazblue you have a number of good defensive tools to use while on defense:
- Barrier Blocking increases the pushback of moves while they are blocked, giving you more space. However, it does drain the barrier gauge (which can lead to Danger state if you don't conserve it), and gives the opponent more frame advantage compared to normal blocking (You're in blockstun for a frame or two longer, IIRC). As you mentioned, it also allows you to block air-unblockable attacks (making it even more important to conserve). This is mostly used in pressure to push the opponent far enough away that you can try to get away from them.
- Instant Blocking decreases the pushback of moves compared to normal block, giving the opponent less space, gives you more Heat, and decreases the blockstun on the move that was instant blocked compared to if it was normally blocked. Typically if you're going to try poke or reversal out of pressure, instant blocking is the type of blocking you want to do.
You can also combine instant blocking and barrier blocking for an instant barrier block (IBB?), which increases the distance even further than normal barrier block.
- Counter Assault is an Alpha Counter that is very important for characters, as it gets the opponent off of you (much like burst) so long as it hits. It gives plenty of invincibility on the move itself (but are generally unsafe when blocked).
- Blue Burst is kind of like a Dead Angle with a different hitbox, and uses up your precious burst instead of your meter. Can be baited in similar ways to Dead Angles.
- Gold Burst is a type of reversal that is +1 on block, launches for an easy hitconfirm, and doesn't take away your primers like a blue burst would. Though this option will be replaced by Overdrive in BBCP.
The other way someone can stop chicken blocking is that, for a few frames while one is jumping, they cannot block. Using a string of moves that have a small gap would give them the time they need to start a jump, and then hit them right in the middle of their jump. Alternately, if you suspect they are holding up-back to try to chicken block, they can't block low in that string. After they get up in the air though, you can make them block more moves (using up more barrier) and they will fall back to the ground where you can mix them up again. Mixing this up with air grab might catch people occasionally (though if they tech the air throw, they get a solid chance at escape).
For frame traps there are two types: The type that you describe is often called staggers, intentionally delaying cancels in your pressure in order to create gaps too small to mash out of. The other type involves any situations that aren't cancels, and use frame advantage from the first blocked move to execute the second one, leaving a small gap. You'll see a lot more of the first one in Blazblue and Melty Blood.
As for online, if they aren't mashing reversals, then you can beat them with a stagger just by delaying your normal pressure strings. If they're using reversals, you'll have to stop pressing buttons (usually) in order to bait (and punish!) those threats specifically.
Hope I helped, even if this information is a bit out of place in this thread. You can also check out the Hazama forums for information on his pressure, defense, etc. (Though for some reason you'll have to go to the archive section for information on CSE...)
