Shroobs were OK, their only problem was the fact that they spoke another language, meaning memorable dialogue was out of the question. Partners in Time was less enjoyable than most of the other RPGs except Sticker Star for that reason. (That and the fact that the most powerful Bros attacks involved consecutively hitting Bro buttons with barely a second's notice infinitely until you screw up)
To me, the X-Nauts did a far better job of the extraterrestrial thing, but I think the Shroobs do still have potential left. But instead of M&L, I think they should return in another Paper Mario installment (unlikely I know, but think about how cool a Shroob partner who wants to stop the invasion from the rest of his kind would be)
But if they do return 'em, I'd hope that the major ones at least know English, (I know the Shroob Princesses knew it, but I don't recall the rest of them knowing it) so they could potentially have cool lines and stuff.
But yeah, my opinions on those are opposite, I like Fawful and Antasma more than Cackletta and the Shroobs.
As for Toad's voice, his older voice>>>>>>>>>>>his new one. That new voice is perhaps the biggest reason why I hate that little bastard.