Couldn’t gamefreak have simply taken volbeat/ilumise and plusle/minun and mashed them into a single pair of designs? They would have then had a pair of firefly pokemon with a relatively exclusive type combination, unique breeding mechanics, and a whole teamwork thing going on, backed up by the plus/minus thing. This would have been objectively interesting, and also not have ripped off pikachu.
And make ‘em Bug/Electric, you mean? Hmm. Yeah, I think quite like that, actually. The cliché that “opposites attract” would tie Volbeat and Illumise’s romance theme together with their new Electricity powers quite nicely. I think the problem is that Game Freak considered ripping off Pikachu to be a virtue of Plusle and Minun rather than a fault. Which… y’know, is not really a position I can understand, but clearly it’s important to them since they keep bloody doing it.