Here are my:
Pros:
-Ash finally got proper rival in form of Paul with their rivalry being played out nicely culminating with great finale and closure
-Team Galactic group of villains was handled in more or less satisfying manner being definitely step up from travesty which Tam Magma and Aqua received.
-Hunter J was possibly one of best villains this show had with writers finally learning how to handle antagonists correctly
-treatment of group pokemon was improved with their personalities coming out on surface more being given more screen time as well some of previous flaws being corrected with writers reducing on number of fillers through various mini arcs like Summer school.tag battle tournament etc
-storyline regarding Chimchar was done in decent manner proving his strength after Paul abandoned him growing in strong Infernap with some sort of rivalry between him and Electivire always being present in a way.
-gym leaders were more fleshed out as characters being properly introduced giving us insight more in their stories along with 4 getting proper debut not being largely ignored like it used to be case before.
Now on cons:
-on of main issues i had with DP was lack of chemistry between Ash,Dawn and Brock group not feeling like family.In groups of two thy had good interacting more or less whether it was Ash/Dawn,Ash/Brock etc but as group they didnt had many memorable moments with interactions seeming forced.
-lack of proper screen time for Brock.While he had some memorable moments receiving his first egg,entering couple of competitions with some of his pokemon getting pretty good treatment(Like Croagunk)he often felt left behind taking backside to Ash and Dawn.Lack of bond between him and female lad and focus big mainly shifted toward development of Ash and Dawn stories forced him sadly out of group dynamic starting to lose purpose.
-rushed league with too many things being crammed in too short period of time
-Misty being completely ignored like she never existed
Overall writing in DP was pretty good when it comes to treatment of character stories with anime plot being treated surprisingly well,but on of downpoints was lack of humor and good character interaction imo.
My guess is they only wanted to have May show up. Back when DP started in 2006, virtually everyone knew and/or agree May would show up eventually and battle Dawn in a contest, it only happened much earlier in DP than expected.
How so?It happened in second season more or less around same time Misty did her regional cameo in Hoenn.
As for Misty/Tracey/Max? I guess the writers felt they had no reason to be in DP.
May and Gary were like the only two important older characters to get SOME role in DP, even if both of them only got like 4 episodes each.
May didnt has any real reason to come in Sinnoh either with Wallace Cup being created solely to give her excuse to be there.If writers wanted to have Misty appear they could com up with various reasons which would justify her presence there whether its for purpose of advancing character storyline or contribute to development of current plot(like May did helping Dawn to get over confidence issues).
Writers had several opportunities for which they could have returned her like:
-coming for some water tournament similar to Whirl Cup to advance her goal
-com to catch some new water pokemon helping them with battling villains like Team Galactic having some relevance to current plot(like Gary for example did)
-play some role in Dawn receiving Togetic
etc.
As we know Misty wasn't fleshed out enough as character having many things unanswered in her story and unexplored(like her goal,potential to find more about past and family,why she decided to pursue career of becoming best one type trainer etc).Her story left unfinished in several areas so its not like writers didnt had excuses to bring her back.
Reason why they didnt i guess is probably because May was recent character which left cast being obligated to give her regional cameo and not wanting to return two previous female leads for some reason in same region.I reckon how they are starting to write themselves in wall risking to have too many previous characters eventually on their hands to have them all returned.
Constant character replacing was proven to be mistake for all aforementioned reasons with older characters starting to get forgotten and ignored in process.If this trend doesnt tone down a bit writers will eventually end up with too many of them to manage to close down all of their stories.
Do you believe those two have a reason for happening? I mean they were probably in the planning stages for BW by the mid-point of DP, so they probably already knew they were going to have Brock leave and Misty was never going to appear again anyway, so they did these two things.
There's a reason Iris and Cilan have somewhat similar roles as Misty/Brock did. It seems the writers used DP to phase out Brock's importance and had Misty be non-existent, just so they could bring in Iris and Cilan to fill their old roles.
First we dont know If and when Misty is going to return.We already saw with appearances if Gary or Jessibelle how unpredictable writers tend to be with this things and if someone so minor could return after years of absence who is to say Misty wont as well?Especially when there are still left loose ends which werent tied up with writers having excuses(reasons) to bring her back having several unfinished things in story.
And second BW trio feels almost nothing like original trio was with there being more differences between Cilan/Iris and Misty/Brock than similarities.Main reason why BW doesnt have contests and Brock got replaced is probably because since 5th generation send out vibe of being more of a "fresh start"than previous ones,with writers waning to mirror those changes with anime explaining why they went back to status of one protagonist and two sidekicks.
Group chemistry and roles current characters in Unova are completely different with ficus in BW being distributed toward development of sidekicks stories barely playing same level of importance to Ash development as trainer like it was case before.Roles Misty and Brock had in original series were to act primarily like Ash coaches and mentors when he was still complete and impulsive rookie.
Reason why Brock was replaced and Misty got ignored has nothing to do with writers trying to "erase their existence to introduce copy of original group".There are no conspiracy theories in children TV show like pokemon with most changes happening to go in correlation with new games.
Your giving them way too much credit.