Indeed. Wild Pokémon make up the bulk of encounters of the game. There are much more wild Pokémon than there are trainers. Making battles trainer-exclusive reduces the opportunities players have to practice their skills and learn the type chart and stuff. Of course, it can still certainly be done, but having more opportunity to practice and learn those skills is a good thing, and since this is supposed to be targeted at people who played Go and may not be familiar with the battle system, I can't be sure that limiting opportunities to practice those skills and leaving them purely to trainer battles is the best move. Either way, it doesn't really seem that consistent with the direction of the game to not have it as so much as an option.
But I'm not really worried about that too much. That's weird, but can still work out. What I'm more curious about is if, since this game is targeted at particularly younger and more casual audiences, whether it will be able to hold their attention without wild Pokémon battles and if they won't just stop playing entirely after a few hours due to everything being even more samey and repetitive than previous Pokémon games.
Of course, some may see that as odd, with how I keep seeing wild Pokémon battles being described as boring and tedious in this thread. But what I mean by that, even if you think that way, is that not only do wild Pokémon battles give you more chance to engage with and learn the fundamentals of the game, but it's also where the personality and differences between different species of Pokémon really shine.
Each Pokémon does its own separate thing, which you have to keep in mind as you battle and try to weaken them so that you're able to catch them. Not only do each of them use different types of moves, often (but far from always) reflecting the type of Pokémon they are, but some are more proficient at and try to hit you from the Physical side, whereas others try and hit you from the Special. Some are particularly speedy and will move before most of your Pokémon, while others are slow as a tank but also hurt like one or have the armor of one. Some Pokémon try to Poison you, others Burn you, some Paralyze, or Confuse you. And yet other Pokémon will try other tricky stuff, like stopping you from using certain moves with your Pokémon, preventing you from leaving the battle, switching witch Pokémon you have out on the field, switching which Pokémon will move first, and all kinds of other stuff.
And regardless of which of those things any particular Pokémon does, with wild Pokémon battles, as you're fighting and trying to weaken and capture them, you get that little preview of what that Pokémon is all about. Not only does it make the encounters with Pokémon themselves more diverse and interesting, but it helps you see if that's really a Pokémon you want on your team and want to use based on what moves it ends up using and stuff (of if it's something that doesn't really interest you after you all). In LGE/LGP, you just have to wait until you capture them instead.
But, moreover, you don't see any of that personality or differences between different Pokémon period (other than just your models) as you're trying to catch them, and instead it will just be the same thing, regardless of what Pokémon you're running into. Doesn't matter whether you run into a Pikachu or a Bulbasaur. A Kadabra, or an Onix. A Kangaskhan, or a Lapras. You're just chucking Pokéballs in the exact same way you would any other Pokémon, while they stand around doing nothing. Whether they're strong or weak, fast or slow, Water-type or Fire-type, Dragon or Fairy, everything just goes exactly the same way, every time.
It's easy to say that wild Pokémon battles don't offer much, especially as you get further in the game, but nonetheless, at least they offer something, make Pokémon feel in some way different from one another beyond appearance. But with wild Pokémon battles removed and just this catching game in its place? If anything, I don't see how that won't result in wild Pokémon being even more boring and repetitive to run into, since there's way less difference before: just chuck balls and wait to catch them while the wild Pokémon does absolutely nothing in return. And I really wonder how long something like that can hold new players' attention, if things are that repetitive, and there's less difference between running into and trying to catch one particular kind of Pokémon versus any other other than at any point in the series' history. It will definitely be interesting to see how that turns out and people end up reacting to that, in any case.
And just one final thing, as far as wild Pokémon battles go, is a bit of nibbling thing, but it kinda bothers me all the same with them being gone, and that's how wild Pokémon battles, in addition to all of the above, make up a good bit of the worldbuilding in Pokémon games. Typically, part of the reason you're even given your first Pokémon in most games is to defend yourself/others (such as a Professor in trouble) from wild Pokémon. But if wild Pokémon are now so docile that they just sit there and let you chuck Pokéballs at them and do absolutely nothing about it, that doesn't really make sense any more. Similarly, when you run away from wild Pokémon, you get the text "got away safely!" which, while it may seem silly later on, at least makes sense at the start of most Pokémon games when they can do your team harm. But now, that text has been preserved in LGE/LGP, but it's even weirder, because even from the beginning the question is "...Got away safely from what? They weren't going to do anything anyway..."
Those may seem like smaller things, and perhaps they are, but just clashing with the worldbuilding of the series like that is still just bizarre to me.
But mainly though, I just can't help but wonder if the younger audiences they're targeting with these games might end up getting bored even faster than before, due to the catching minigame getting more repetitive than wild Pokémon battles ever did and making different species of Pokémon feel a lot less different and interesting than they actually are. Just seems like one of those changes that could have the exact opposite of the intended result to me, but only time will tell I suppose.