Parker would make for a natural progression for Nintendo to release Light Switch* later down the road for folks to upgrade, and by then, 16nmFF will have come down further in price anyway. Nintendo wouldn't have to pay much for ASIC R&D, and perhaps would only just pay for licensing the chip design & fabrication.
*Charger & dock not included.
Mobile mode would then feature lower power consumption for OG Switch games, then options for devs to utilize higher clocks for new games.
Docked mode is easy enough since they already have a framework for GPU clocks. Whether they expose increased CPU clocks down the road ala PS4 Pro boost for PS4 games remains to be seen, I suppose.
Denver being disabled in Max-Q is a funny coincidence, n'est pas. Memory contention with Denver + A57 + GPU would be interesting to see, but Denver may simply be off-the-table just like how the A53s are disabled for Switch, and that Max-Q mode is essentially tailored for the next Switch revision.