I think there's definite positives and negatives for both sides and they're going to incorporate elements of both into 10th gen. It's quite common that they remove a feature and then bring it back shortly later, and right now the games seem to be building on each other (heck, LGPE was incredibly controversial at its release and we're still seeing its legacy on the gameplay with the positives added onto the main gameplay and polished to make them more likeable). LA is much more action oriented which makes the gameplay feel more realistic, but SV opens things up even more. I think by now Game Freak probably knows that LA's action based gameplay, being able to catch Pokemon and be attacked in the overworld, is universally liked so similarly they'll just incorporate that into 10th gen while building on what SV did. I think 10th gen might look something like this:
- Fully open world like SV. Hopefully with a level scaling mechanic added to make it easier to complete content in any order you want.
- Wild Pokemon can attack you like LA.
- Ability to throw items and Poke Balls like LA and to trigger Let's Go mode if you throw a Poke Ball with your Pokemon in it at something other than a Pokemon. In addition to collecting items and Auto Battling, Pokemon can now interact with obstacles in Let's Go mode, such as breaking rocks, ramming trees, etc.).
- Return of ELs.
- Return of the Request system from LA.
- Keep SV's three stories system, possibly with something similar to Nobles taking the place of Titans.
- Ability to craft regular items, not just TMs, like in LA.
EDIT: Also this is a minor thing, but it has a major impact: I don't like that SV doesn't play the shiny jingle in the overworld like LA did. Makes it very easy to not even notice when a shiny has spawned in the overworld if you're wandering around exploring, finding shinies becomes a game of find the needle in the haystack without it. Whereas with LA, if I was just wandering around the overworld, the shiny jingle would catch my attention and let me know to stop and look for it instead of totally blowing by it.