Of course. And I've heard casual fans and even people who hadn't had anything to do with Pokemon at all before say that they'd be really excited if there were more. I'm honestly not arguing for this to implement more complex mechanics, just more Pokemon for collection purposes. Because this game is all about the collection.
I know it may be hard for people who have the nostalgia for gen 1 and stuff like that, but honestly, I believe that if they introduced more Pokemon in batches, that'd be a great way of constantly incentivizing people to go out and catch Pokemon. For many people new Pokemon carry this stigma of not being there in the 90s for them, but for many all of this is new, so more Pokemon that are equally new to them really shouldn't be too problematic.
I mean, imagine you know nothing about Pokemon and you've caught most of these and you still want to play but it's become a bit more routine, but syddenly there's an update and there's like a whole bunch of new Pokemon and you're like "HOLY TROUT!!!!!"