Karsh is the man and was part of my original endgame trio.

What does the bit about Lavos in the Dead Sea say? Did you find it?

Also apparently a dead Johnny can be found there which is appropriate since I just got done racing that jerk in my current CT run. (it's going slowly. It's not a priority for me)

You're totally right about the filler bosses though. I had forgotten about that until my last run. There are also a lot of bosses who don't give Star Levels in the game but they're usually optional like the octopus or Dario. I suppose in NG+ they add up to 99 and then you're invincible.