I like the concept of convergent evolution. As long as it doesn't take up a huge portion of the new roster, I'm ok with it sticking around.
I like the concept of it too, in theory.
I guess more than anything I feel suspicious about the motives behind it. I wouldn't like to see future gens made up by a large portion of convergent Pokemon.
Also, I wish Wiglett had more differences to it. (like if it's nose was actually a mouth with one tooth like in the Diglett memes) Like when you look at the Hummingbird Moth closely it's clearly not a Hummingbird. I don't get the same vibe from Wiglett, it absolutely could have been a regional variant if they had wanted it to be. (I know it's an eel Pokemon but they didn't have to classify it as an eel, it could have easily just been a water Diglett)
Also I wish they gave it a different name to differentiate it more from Diglett. It's like on one hand they're saying it's a new Pokemon and on the other hand they're saying it's not a new Pokemon. It's sort of jarring.