Look, let's be honest... as bad as 4th and 5th Editions are, they cannot compare to the clusterfuck that is any Palladium game...
Palladium isn't a bad system in and of it's self. I've been running Heroes Unlimited, Ninjas & Superspies, Rifts, Nightbane, and Beyond the Supernatural campaigns since the mid 90's. The various character options in each game system
are not balanced, but the palladium system wasn't trying to make everything balanced against everything else. It was trying to simulate comics, high fantasy, post-apocolypse fiction, and so on. And let's face it, guys like Superman, Flash, Hulk, and Thor
are not balanced when compared to even most of their villains. Robocop is not balanced in
his setting, and that's the entire point of the Robocop movies. Gundams aren't balanced, and never were. They are so far beyond any other mobile suit tech in their settings that it takes an absolute rookie piloting one for even the best of the best to hold their own. If the pilot is skilled? They can wade through entire armies without any backup.
It's up to the game master to balance things in a Palladium system game. Don't want invulnerable super strong bricks flying around? Then say "no" when someone wants to be invulnerable. I
always do, because Invulnerability as it's written in Heroes Unlimited is just plain broken. You're 100% immune to anything that isn't magic, take half damage from magic weapons, but "physical" spells like fireballs and electric bolts do absolutely nothing to you because they're a physical damage effect and you're immune to those physical effects. Did everyone make a "street" level character? Then tailor their opponents accordingly.
EDIT:
As for the Rifts setting specifically, I think what people forget is that the Coalition States
are not suppose to be heroes. They never were. They
claim they are heroes, but they are suppose to be the central badguys of the North American continent. A badguy organization that is so powerful that fighting them is a dangerous thing to do, so most don't even try fighting them. Hell, one of the campaign arcs for Rifts is The Coalition
going to war and wiping out the Magic Kingdoms, who are a simi-good society, for the inexcusable "crime" of using magic and psychic powers. The two weren't even in competition for resources. The Magic Kingdom was set up in an area the Coalition had zero actual interest in. The Coalition States aren't heroes of the setting. The heroes of the setting are
independents like Erin Tern who travel the world exploring and documenting things, as well as organizing the defeat of such threats as the Four Horsemen of the Apocalypse.