Short version: NO! DON'T MAKE DIGIMON MORE OBSOLETE!
Long version: A lot of the points I was going to say have already been said, that there's already something temporary in the form Mega Evolution and Gigantimaxing, that if "de-evolving" was allowed it would make the themes and consequences of evolution pointless, and, lastly, it that it would be even more similar to Digimon, which it already got with Mega Evolving.
And that last one is important to me because, well, as much as I love Mega Evolutions, I still hold Digimon close to my heart as I do with Pokémon: I might not be obessessed with it at the moment, but it still means a lot to me. Where Pokémon feels like fantastical animals and friendly monsters, Digimon feels like if you did that, plus the treatment of the Mystery Dungeon (as in the Pokémon can "talk" and have their own societies with little to no humans involved) and using mythical figures (Knights of the Round Table, the Olympians, etc) just as much as mythical monsters (dragons, serpents, unicorns, etc).
So I would very much not want to see Pokémon get compared to Digimon even more, at least not in the vein of "Oh there's temporary evolutions! It's just like Digimon!" because, again, I like them both for the creatures the franchises are named after.