Are you joking? Did you really list megaranger, maskman, and ohranger?
I agree. MegaRanger is an awesome name IMO. So is Maskman.
I like the name OhRanger now but I could see how "Oh" might be awkward for an American fan. Because when we look at that we might either think of "oh" as an exclamation or a sound indicating something else so it seems odd. But once I found out "Oh" meant king then it seemed much cooler.
Though you do have a bit of a redundancy if the team is technically KingRanger but there is also a 6th who is called King Ranger. But since he's the hero who kicked the Baronoia off the planet in ancient times I just figured it was UAOH deciding to name their Sentai after him.