Brock being a "familiar face" lost its novelty in AG. I believe the original reason Brock was kept for AG is the writers DID originally want one familiar character there.
The DP trio would have been more interesting if say Barry were a travel partner instead.
I disagree.Brock still retained that novelty of familiar character in AG being known for being obsessed over girls,being irrational over finer things in life and wccentric while at same time being capable,collected and mature when it comes to pokemon and bringing order when conflict arises between group giving us often character which had that level of mystery and stability balancing out impulsiveness and tension between cast.
I actually liked his character quit a lot in Hoenn and Battle Frontier feeling more intriguing than he really was in Johto.I watched Johto several times and i can safely say how he suffered the most there as character(definitely more than TR or Misty did),and it was refreshing to see writers fixing mistakes with him in AG becoming valuable and enjoyable part of cast again.
Talking about Barry,i dont think things would have been much different even if he replaced Brock in Sinnoh.DP was designed to promote Ash and Dawn friendship and their focus on career and whoever was third party there would probably suffered from same problem Brock did ending up neglected.Problem wasnt in Brock in DP.,but in writers incapability to balance out screen time between three characters at same time in cast adequately.
I really don't understand how you can sit through something like the Johto saga, when the show really was bad in most cases, over sagas that are actually good and entertaining like AG and BW. Keep in mind I also liked most of DP, so I am not saying DP is bad either.
Maybe in your opinion,but opinion fro one individual cant speak in name of everyone else.
I can understand why you didnt liked Johto,it wasnt my cup of tea either,but at same time i dont consider it as worst region having good chemistry between Ash,Misty and Brock,many enjoyable episodes,mini arcs etc with some things being improved compared to Kanto.
Some people liked this series more than they did within AG,DP or BW.People have their reasons for not liking certain regions,while enjoying in others.
Which is fine because world would be very boring place if everyone had same opinion.
Iris doesn't have a fiery attittude, she doesn't have a temper at all really nor does she argue with Ash. She calls him a kid and that's the extent of it. She's really not like Misty personality wise at all. She doesn't obsess over dragons the way Misty did over water pokemon.
While i agree you cant generalize characters on one to two traits,because there is much more to it.I suppose reason why some people view Iris similar to Misty is because of their cynical and snarky side liking to tease.
That and their fear over specific type of pokemon,but agreed hardly enough to be considered as clone.
Which is exactly the reason a lot of people felt the DP trio was stale. While people might have liked Dawn herself, people also watch for a group dynamic. Since Dawn/Brock didn't really have any type of chemistry, it was little to go on.
Majority isnt always right.Just because some thought DP group was stale doesnt mean it was stale to everyone.People view things from various points of perspective having different preferences.
There is no right or wrong answer here.
I'll ask this, don't you think this is why Brock finally left after staying all this time? I think after the DP series, the writers realized they needed to go back to the original formula and back to characters who have a group dynamic. Brock probably survived through AG and into DP probably because he still fit into the Hoenn group, and kept his character entertaining.
I think it has more to do with BW games than anything else.BW games were revamped alot more than it was case with other games in past trying to give "vibe of fresh start"with several changing happening from contests being gone,Unova being portrayed as far and isolated region as well not having anymore second side quest.
Writers probably wanted to mirror those changes with anime explaining why formula went back to one main star and two sidekicks as well why another new character joined main cast at expense of Brock leaving.
If BW games didnt had so many changes Brock would probably stay in main cast past Sinnoh.
About intention being to have anime go back to original formula with Unova,logic dictates how writers would probably reunited original trio instead.It would have made far more sense,better displaying intention of "anime going back to its roots" pleasing many fans.
BW currently are viewed nothing alike,like Kanto was with BW trio while having good chemistry operating on completely different level serving different purpose.
When DP started it was clearly only about Ash and Dawn, and Brock felt detached from everything. Two people alone don't make a group.
Which leads me to believe how main reason behind Brock neglect in DP was because attention of anime was mainly directed toward focus on development of two co-stars(Ash and Dawn)and their friendship forcing Brock out of group dynamic,not having much things in common with Dawn to connect on closer level.
However from what i noticed DP focused more on his breeder career than Kanto,Johto or AG ever did giving to character some development.However while DP did more about Brock career of breeder getting his first egg,participating in various contests(like triathlon,pokemon transformation contest,summer school arc,tag battle tournament etc)he was at times so much sidelined that you could get impression how he didnt developed at all.Although he did to some minor degree coming to realization over course of Sinnoh how doctor is true calling he wants to pursue with people often overlooking such details.
Speaking of Dawn she wasnt my favorite female,but i have to say she was one of reasons why DP was entertaining to watch(just like may 0or Misty contributed greatly on appeal of respective sagas they were part of).What i liked about her was that she had good interactions with Ash,Zoey,Ursula or Kenny being good character,interesting story and development she went through gaining tremendous growth as coordinator with culmination of hard work being achieved position of runner up in Sinnoh GF.And all that burden and pressure she had from mother,her rivals and friends she carried on back having to prove her worth as coordinator and fulfill other expectations made me root for journey and progress she made.