Honestly, I don't understand why you blocked trade between Diamond and Pearl.
I think it was yesterday (or maybe Sunday?) that a guy in Platinum, former Diamond player, told me he had "transferred" via Market (paying 3 diamonds for "Both Worlds") some pokemons, so that a friend of his from Pearl would get him these pokemons.
I thought "Oh my! what a good idea, I know I have to start from scratch, but at least I'd love to get some pokes from my beloved team".
I was trying a moment ago to transfer one pokemon in this way and trade between both worlds is disabled.
What is wrong with asking a friend from Pearl to get you some Pokemons to Platinum? It is not stated anywhere that doing it is cheating. Also, it is not like you are going to transfer all of your Pokemons... noteworthy it cost 3 diamonds per offer in Market for both-worlds and they are not cheap right now. Furthermore, I believe Pokemons will devaluate a little bit in Platinum, depending on the amount of Pearl players that move there; therefore I don't see how doing this will affect the market in Platinum.
And also, you already said that some rare pokes (Eevee and Klefki) were not allowed. But if you (Staff) think allowing us (people who can afford paying 3 diamonds per both-world transaction so we can get some pokemons [In my case, like 7 - 8, my team]) might alter the market in Platinum, which I strongly believe it won't, then put more restrictions like "only 1 pokemon per player". That way, for instance, if my friend has a Milotic and I have a Milotic too, of course my friend will tell me "Sorry dude, but I want MY Milotic", this way the amount of pokes would be "controlled". But honestly speaking, I don't think it will alter the market at all.
I know... I know... I know you said "start from 0". But Pearl players going to Platinum are not starting from 0. As many have said before, It is not fair.
To be honest, I decided to quit Diamond and start a new character from lvl 10 in Platinum, but with hope that I could get my Team thanks to Pearl friends (the Merge). These two last days that I have been playing in Platinum, I was so amazed how fast pokemons lvl up, I even reached lvl 82. I really like Platinum. However, some pokemons and specially TMs are very expensive or not at all for sale (and I can't even make TM Task because I can't "unsubscribe" my Diamond character from TM Task). I am not going to go through hell, skipping school, skipping family events, "donating" for more diamonds to make cash, skipping life... to achieve AGAIN what I have achieved in Diamond, which honestly is not that much, but since it was Diamond it was HARD to get.
I used to have fun. Now ain't no fun anymore.
Retired~