You'll be surprised
.
Anyways, it appears as though Mario Kart: DD 'may' well be online, with no subscription fees to pay. If this is true, makes you wonder if F-zero and future GCN multiplayer games (like SMB3?) will have similar, inbuilt tunneling software, which wouldn't require the use of a PC to play the games online.
As for the 4-player pacman, I'd rather play it first before deciding whether it has revolultionised the multiplayer genre or just plain sucks. I doubt either is true, but it'll be hard to find out how good/bad it is since it'll be hard to find 3 other people with GBA's.