For the record, that line was added in the localization, I do believe.
Besides, I don't see why a romance involving a back and forth tease fest is inherently better than a one sided one. It really has to do with what the individual prefers in a relationship, and pit very well may prefer what he has with P-money. In all honesty, the games make it look like he does.
And, while this is pretty subjective, I don't really see how Pit and Viridi mesh better. They argue a lot. He always seemed to get along so well with Palutena, it was always pretty remarkable how much they respected each other and enjoyed each other's company. I guess that's what I always liked about the ship, among other things.
Actually, in the Japanese version Palutena just straight-up calls Viridi a tsundere, to which Viridi replies with even more generically tsundere lines. That's hardly an improvement. The part that was added in the localization was the PalutenaxPit shipping scene in the ending of the original Kid Icarus.
I think, personally, Palutena has a much more one-track personality than either Pit or Viridi do. Palutena is all "everything for the humans!" and Pit's like "actually, Viridi has a point, but I think she's being too extreme about it" and Palutena just goes all yes-man mode. Viridi starts out with "humans are terrible and I hate them" and eventually is implied to change to "UGH! I
want to hate humans but they've proven to be all right on occasion. I hate you for making me not hate them, but I like you!"
Pit gets along well with Palutena primarily due to hero worship from what I can see, and she gladly takes advantage of that. Pit occasionally says a few things that indicate that he's skeptical of Palutena's perspective on occasion, but then goes right back to yes-man mode. A lot of their relationship seems to be based on them agreeing with each other on principle, and I'm not always convinced that they actually think along the same lines.
Also, the conversation about clubs between Pit and Viridi. And the one about blades.
And as a matter of subjective opinion, just like Pit's yes-man relationship with Palutena causes her to behave in a similar manner in return, I feel like Viridi's tsundere attitude towards Pit results in him almost instinctively behaving slightly tsundere in return. Example:
Palutena: "Looks like Little Miss Cactus has a soft spot for Pit!"
Pit: "Really? 'Cause, uh, I don't think you're all that bad either." (Normal Pit.)
Viridi: "Shh!
Quiet! I AM
DEFINITELY NOT DOING THIS TO HELP YOU, PIT!"
Pit: "Fine! Then I'm not doing this to help you either!" ("Just going along with it" tsundere Pit.)
VIridi: "Ugh!
This is why I keep trying to kill you!"
Then again, I have a personal alternative character interpretation that Pit is actually, in some ways, a lot smarter than he frequently comes across as and occasionally likes being comic relief, and is actually pretty
laissez-faire about some things and enjoys just going with the flow. The reason for this is that sometimes he actually says things that are pretty intelligent, but then there's the "So you know how a chicken takes three steps and then forgets?" joke.