>>53952575I think that the argument as a whole has two sides to it, if we get back to OP question. I can see somebody, who is competitive, to want another option to counter Megas as opposed to having to run your own Mega.
But at the same time, I never played competitive, and liked Megas. I don't feel laziness in development had anything to do with the choices made, as it was a gimmick that they wanted to showcase.
If I, whilst playing XY over 10 years ago, didn't want to use Megas, I didn't and don't remember any problems against NPC trainers. But I'm pretty sure I used Megas, because they were new to the series, and I liked them.