Yes, BW was a test for XY. But DP was a test for BW, and so forth.
They probably wanted to change up DP's slow pacing, hence BW Season 1's faster pace. Maybe they were questioning Team Rocket's relevance, enter black uniforms. Ash, Dawn and Brock had quite a dull relationship with each other, enter Ash, Iris and Cilan's more lively chemistry.
I'm not so sure I can trust the writers to correctly identify the good ideas BW had hidden behind the poor execution though. They're probably more likely to go in the opposite direction and try and make a not-BW series when ideally the best of all series should be combined into something amazing.