If anyone thinks PK Fire is a bad move, I want to play them. Specially you Masky *glares with my eerie eyes*
DIing out of PKF has a few good options. Roll out, DI down and spotdodge, or jump out. All are easily punishable. ROlling can be dealt with using the usmash or dash attack. Spotdodges are done in by the usmash, and jumping out is very easy to wreck with aerials.
If you are being punished for PKF, you are obviously using it very very badly. I hardly ever get punished for it, even when powershielded. As long as you pivot and firedash, you'll always be maintaining a safe distance. If you PK Jump, you get massive range on it. I hear people complain about being punished for it all the time. They're doing it all wrong. If you lag cancel with an airdodge and spotdodge immediately after, it can be difficult to counter. Possible, but difficult for many.
People have to realize that PKF is still a projectile and can be used at moderate ranges from Ness to handle opponents with good range. You CAN get attacks out of the PK Fire pillar if you play smart with it. If you're gonna be the basic Ness who always grabs or bats the PKF, of course you will think PKF is bad; you're using it wrong. It's like trying to use bananas to camp instead of control the stage.