Did I like the Poketch? More or less. It was certainly useful and a step in the right direction for Touch Screen controls in Pokemon. The overabundance of somewhat unnecessary apps cluttered its usefulness, and Pokemon Diamond and Pearl didn't even have an option to go back to the last app. (Thankfully, Platinum did.)
I'd like to see the basic use of the Poketch return, especially the ability to swap your Pokemon and use items without having to pause (which the Poketch didn't do). Some other apps could be optional, like the type-advantage app that's only too useful for beginners. Perhaps the apps could be stored in the PC in case you didn't want to clutter the Poketch.
So yes, I'd like to see it return, but streamlined even further. HeartGold and SoulSilver basically just moved the typical pause screen to the Touch Screen, which was interesting but felt like a step back from the Poketch. I haven't played Black and White, but its C-gear feature sounds a bit like a downgrade to me as well. The Poketch was probably the best use of the Touch Screen in a Pokemon game.