Agreed, and i think we're going to see the same from many 3DS franchises. The Switch is going to force a lot of SD franchises to jump into HD development, which is going to make porting many of them to the PS4 an attractive proposition (especially Japanese titles looking to broaden their international reach). Likewise though, the Switch being a popular HD system makes it a lot more viable for titles that have previously have skipped the 3DS because of technical limitations.
All in all i expect both Nintendo and PlayStation gamers will be pretty happy. They're going to 'lose' exclusives, but they're going to gain access to more games. Seems like a good trade to me.
I think that's great for these mid-range type of games. Sure, it'll go to PS4 first, but porting to the Switch may not be as complex for Japanese developers. Plus, this can give extra life towards these types of games on Switch due to its portability factor, which is something Square Enix pointed out and are showing with games like Octopath Traveler, I am Setsuna, and Lost Sphere. And as you said, the 3DS franchises can potentially grow and do more than they were able to do on the 3DS due to technical limitations. Thus, series like Professor Layton, Ace Attorney, Bravely (if Octopath Traveler doesn't become Bravely by name), Etrian Odyssey, Story of Seasons, and SMT (which is already confirmed to release an exclusive to the Switch).