This! People who are saying that old characters are being forgotten in Japan, and that's why the Japanese writers made Dawn so similar to Ash for the Japanese audience are forgetting the fact that the oldest of episodes are still being shown on Pokemon Sunday. Heck, two weeks ago they showed how Ash got Charmander..
So I don't get why people are saying that they are retelling Ash's story through Dawn. Sure there are parallels, but Dawn's story is totally different: Did Ash ever go through depressing losses in Kanto?
Ash can't go through depressed phase for more than a episode because of his shear determination.
Did Dawn ever receive pity ribbons?
Most notably: did Ash win against his major rival in the indigo league???
We don't have a confirmation of Dawn winning over Zoey till now.
Comparing Pikachu's and Piplup's moves also falls short of complete comprehension to me..
Pikachu: Electric type attacks (basically all of them in gen1) and quick attack. Basically his elemental type attacks, and moves concerning speed.
Piplup: Whirlpool, Bubblebeam, Hydropump. I agree that there is a slight comparison to Thundershock/bolt and Thunder (as in 3 attacks of the same type), but Piplup also has Bide and Peck, which is a defensive and a move of another type.
If you compare Pikachu moves from Original series to Piplup's move from now then you might see some close connection.
For STAB moves
ThunderShock=Bubblebeam, Thunderbolt=Whirlpool, Thunder=Hydropump
Other types moves,
Quick Attack, Double Edge or Agility = Peck or Bide, but if we go by AG then Iron Tail= Peck and Quick Attack=Bide.
Lousy match up but I think you got the point.
What I'm trying to say is, they probably aren't trying to retell Ash's story through Dawn, since Japan (the writers top concern) has Pokemon Sunday to show his early journey. What I think is that Dawn's journey has minor similarities (Mamoswine) just because of the old saying: 'if it ain't broken, don't fix it'. Same with Piplup unwilling to evolve. The writers probably thought: How can we give this penguin more screentime, without letting it seem like hogging? Lets give it a reason that's worked in the past.. oh yeah, lets make it stop evolving, which would make the viewers sympathetic for it and love it more!
They tried many similarities between Pikachu and Piplup throughout the DP saga. But Piplup not evolving was to mirror Bulbasaur and this time round it was dumb cause reason was imperfect.
But at the end of the day there were many more similarities between and May and Dawn and their Pokemon than Dawn and Ash.