I agree with every single letter in your post. The only reason I still watch DP episodes is because of elaborate story-line built around it.
Face it, had Ash's character ever been tested as much as he was by Paul? Almost every Pokemon of Ash has been developed well in DP.
Except for Starly, each of his Pokemon had its own story line as they grew up to their final stages (except Buizel the rest four evolved, a significant achievement for Ash). All of his DP Pokemon were memorable.
Can we say the same about BW?
Oshawott: He has the most personality of all his Pokemon, but I haven't seen any growth since ages.
Pignite: Perhaps the only Pokemon that was slightly developed.
Snivy: They showed her to have a unique characterization at first, but completely ignored her after it.
Scraggy: Aside from Focus Blast, where was his development?
Less should be spoken about the reserves. They received the worst treatment ever since Kingler.
Best Wishes was poorly planned. They had some wonderful ideas that could have kicked any saga's ***, but they managed to fail each and every of them. At this point, I am utterly confused as for why I am watching this show.
Of course I am not saying DP deserves a 10/10 or something. It had far too many flaws like the sub plots were heavily reliant on TR. In fact TR became extremely annoying by the end of DP.
Ash and Dawn had good character development, but Brock on the other hand was poorly treated.
And not to mention the saga was extremely long and so seemed boring at many points.(remember the fifty episodes gap between the 7th and 8th?)
After seeing Best Wishes though, I'd perhaps say I would rather bear the long and tedious arcs of DP than see an improperly written, extremely rushed saga like Best Wishes.