I made a smooth-talking agent, got bored. Made a Cyber Ninja, got bored.

Any ideas to alleviate this? I think a fun RP and build would help.

Meh, just stick with a character.
My Cain Ramirez character, a hunter who isolates himself from the outside world, was a bit of a drag to play during the first act of New Vegas.
Since he didnt' like to involve himself in the affairs of others there wasn't much interaction with the civilized world.
But when I came to Vegas there was quests that fitted the character more and it started being a lot more fun.

So stick with whatever character you're making, dat be my suggestion.