I like Mushroom Plains. All the others sound... stupid. Hell, Mario Party's mini-game titles are 50x more interesting than those MarioWiki suggestions.
Anyway, I really don't mind the generic numbering system whatsoever. Nintendo would probably come up with names even worse than the MarioWiki ones. Nevermind the numbering quickly becoming confusing for some when it turns into:
Donut Plains 1
Donut Plains 2-B (for alternate courses. Putting "Donut Plains B" would be more confusing than World 3-B, for example.)
Chocolatey Forest Extravaganza 9
Super Magical Dust Land 4-Ghost House
Guilt-Ridden Deadly Poison 4-C (Anyone who gets what game that's from wins)
Sea of Shifting Sand Land Castle
Fires of Hell 7-Back Door
EDIT: I'd like to share some sound opinions, advice opinions, and glitches in the game.
Sound: Why did they stick with the DS "hurry up" and "you're dead" sounds? I don't mind the "you're dead" one, but they sound like the same sound quality as the DS and they're both a lot quieter than the other songs/sounds... as if someone in the recording studio held up a DS, waited for the timer to reach 100, then quickly held it up to the microphone and recorded it.... and subsequently used that.
Glitches: When you unlock the secret thing and, as a result, collect all the star coins in a world, you get a notification that you've gotten them and now can play one of the things at the secret thing. Well, I got the notification for all worlds except when I finished World 3. Strange. Also, has anyone else noticed that the game freezes for a split (but very noticeable) second every time you get a Starman and if you touch the flagpole when you have a Starman?
Advice: Couldn't Nintendo have kept the advice to a minimum? Before you assume anything, let me explain: You know the little icon you get over your head when you get an item that is spin-jumpable and when you get near an object you can pick up? Couldn't it have just done that the first time you encountered a shake-the-controller [fixed for Toad] item/object, then never showed its face again (or at least have the option to turn it off)? Do I have to be shown what to do every time I find a Propeller Suit and every time I run into a set of ice blocks/POW blocks/whatever in a level until I do it? They at least could've taken the Mario Galaxy approach (which is still annoying) and just kept the permanent instructions in the levels you encounter a new gameplay element in (Battlerock Galaxy, Space Junk Galaxy).
Also, another thing: Must I be forced to look at the "Hey just lettin' ya know! Don't be afraid to use your items to clear a tough course! Press 1 to bring up your inventory" notification every time I finish the item mini-game?