Why is everyone shocked about the abundance of 1ups? It has been like that since SMW, heck SMB3! The Mario games have always been generous with lives but IMO that does not make the games lacking in challenge. Maybe less frustrating in that you don't have to restart a huge chunk of the levels but I don't really find that fun going through everything I've done before.
I've gained 99 lives on a couple save files, some with and some without effort. The thing is, after I hit the mark, I was still gaining an average of two or more lives per level, not including the one for hitting the top of the flagpole. Virtually any stage I'd die in, there'd be a 1-up or two in-between the starting or midpoint and where I'd die.
There were a lot of one-ups in earlier Mario games, but this one truly has balanced the number for multiplayer. It's not a complaint, not at all, but rather just something worth mentioning out of novelty. Lives mean a lot more with each additional player, which is just something to make the game more fun with a co-op/counter-op type of style.