Confirmed. I own both Diamond and Pearl.
Miguberu
I have Diamond and I must say I love it but:
1) The trainer(you) is slower than in other games.
2)It sucks that you have to wait becuase "its saving too much data".
3)The PKdex is completed by seeng PKM not by catching them.
4) I started with Pochama(water) and most of the PKM I encounter are Geodude or Ponyta wich isnt much of a challege and doesnt give me areas to capture diferent kinds.
1) I haven't really noticed that yet.
2) It only does that if you have been playing for a few hours without saving or get a badge shortly before saving.
3) The dex is not completed. It only counts as "seen" not caught, but the goal is still to catch 'em all.
4) Try the Great Marsh, or see all of the new pokemon in order to complete your "seen" dex, to get the national dex from Oak, then you will be able to port over your Ruby/Saphire/Emerald/Fire Red/Leaf Green pokemon.