That was a baseless rumor, it was never fully confirmed by anyone involved with the games. The 5th gen only thing was a direct quote by someone involed in the game creation, on his blog.
Weyard said:
Well if you'd get your facts straight for more than a minute at a time you wouldnt make posts that make you look foolish, then you wouldn't have a multitude of new replies.
The only way your "logic" would hold up is if the person which you are using it on is blind. There are far too many similarities for it to be 100% not his evo. I'd like you to hit up my post about a Sableye evo while your at it. I'd like to see your word on it XD.
"Get my facts straight"? What the heck? My facts have been consistent since I first started posting. I haven't been "changing my argument" or using inconsistent facts. In fact, I'm the only one USING facts and probability based on all factors. Wheras everyone else is saying "PINK HEART SHAPED WATER TYPE", a perfect example being mybrilliant's post.
Also, my posts are not making me "look foolish" as I'm the only one that is coming up with logical BASIS for my theories, backed up by many factors. The ones looking foolish are the ones saying "AH DURR HURR PINK FISH GOTTA BE LUVDISC" These are the ones that are blind, they are blind to EVERY OTHER FACTOR besides the physical appearance. Which mind you, is ONLY the vague heart shape and pink colour.
And it's taking me a long time to post because I have more to say then just "IT'S OBVIOUSLY LUVDISC JUST DEAL WITH IT"
As far as the Sableeye example, I would take other factors into consideration. First of all, Sableye is a bad example, because it's a Dark/Ghost so therefore it's highly unlikely to get an evolution in any case. Secondly, I wouldn't believe it was an evo, because of all the other factors already involved with Luvdisc. However, if Sableye was featured in the anime, or was being promited in some other way, and then suddenly has an evo? THEN I would think it was an evo to Sableeye, since it would have a REASON to be shown in the pre-relase stuff.
Please keep in mind that Electivire was the ONLY Pokemon evo from an old gen to be shown in D/P pre-realease stuff, and it's because he was being majorly featured in the anime as Gary's Pokemon before D/P came out. Luvdisc on the other hand is a forgotten Pokemon that is NOT being featured in the anime.
Now I will post my comments in bold in response to your for/against list.
FOR:
-Pink
-Heart shaped
-Water type
-Is a sun fish -
Luvdisc was not in any way a "mola mola" fish. It looked exactly like a heart, with it's mouth coming to a point. Mamanbo looks like a mola mola/ocean sunfish.
-Luvdisc was in need of a new evolution -
OPINION
AGAINST:
-They would never do it -
I never said "NEVER", I said it was highly unlikey
-It would go against a previous statement made by GF. This should read COULD go against it. As I said before, it could be a hold item deal, which would fit their statement perfectly fine.
This is not a legitimate reason to show it in the pre-relase material
-NO WAY they would show post-game/new evolution pokemon at this time/opinion
This theory is based on both the statement made by GF, as well as the fact that no new evo Pokemon besides Electivire were shown in D/P prerelease material, and they never even made statement like they did with the 5th gen
-Luvdisc would be a random choice for such a revelation if it were to have occurred that way/opinion. Or as you put it "Luvdisc is so totally random and has NO reason to be promoted in the pre-release material"
This is more fact then opinion: To promote an evolution of a Pokemon in pre-release material, without any ulterior motive (such as being in the anime) directly contradicts the statement of the game being a "surprise" to everyone and being 5th gen only. Luvdisc, or any other previous gen Pokemon, has no legitimate reason to be shown in pre-release materials after that statement was made, unless it is going to be featuured in the anime/movies or factor majorly in the games in some way. Examples being the 3 mystic beasts being shown as they tied into Zoaroak in the latest movie.