>>13407733This.
What needs to happen is a slimmed down Poketch-type device (there are too many bullshit apps). The C-Gear has a lot of cool functions, but the thing is, it could all be incorporated into a Poketch-like system. We could literally have our cake and eat it too. It could incorporate the useful aspects of bottom-screen menu, to boot.
Seriously, organize it like a phone screen, with multiple apps to click on. Pokemon, Pokedex, Bag. You can make shortcut apps to items you use a lot (Town Map, Dowsing Machine, Fishing Rod, C-Gear). No, it doesn't entirely make sense, and I don't fucking care.
Pokemon following you around was fun but not really useful and didn't genuinely add anything. I missed it for the first bit of BW and stopped thinking about it. I would rather they focus on legitimate gameplay improvements. If we could have both and not face any slow-down that would be wonderful, but I would rather have the more dynamic environments of BW than the Pokemon following me of HGSS.
Anyways to answer your question OP, there are two teams that work on Pokemon. HGSS were built by a secondary team on top of the already existing system, while the main team was working on BW. Concurrent development -> loss of "bonus" features.