I was fairly sure pillaring was to do with shield pressure.
Yeah, it was melee's dair to shine on the shield as it gave minimal room for the person to counter attack, thus eating their shield. (However it worked well can a combo to attack due to the coolness off popping someone up to dair them again repeat. So then people thought that pillaring was a combo"
Another "pillar" was the downthrow to dair to downthrow. But this is not pillaring at all. It's just an extension to the chain grab *cough*combo*cough*
I thought a pillar was when you pop a foe into the air and combo them up there. :/
Man I'm sooooooo pissed now! I have been practicing over and over trying to master spacing. I can now do it without a suicide.... like ever. I was happy today when I brought a CPU in training mode up to 500 and some damage only from spacing and I didn't die from phantasm at all during this time. I finally thought it was ready to put it into my game play. Untill I realized it is almost impossible on wi-fi. I never noticed the slight lag on there. You notice it when spacing though. So yeah... I hate wi-fi now. -_-
Now for the real question is "What to do to pop the opponent into the air to **** face":
Phantasm does work, however iap tends to spike them down.
Utilt to any aerial (you could nair them at low % for another utilt. Or you could dair spike to another utilt.
Dtilt is also a another good move and can also shield stab.
And spacing is simply creating space for yourself to either stay out of their range to avoid attacks/counters, or keep close to keep them in range of your attacks/counters.