Is a hardrive needed for replays?
Sakurai announced that you will be able to save and send up to three minute replays of battles or other modes. At first glance one would think this would require a very large amount of data to save that much footage of a game. However, depending on how they save the data, they could keep extremely small sized save files. When looking at a game like Halo 3 that allows a similar feature they manage to keep two minute save files down to an extremely small 100 Mb. Considering the large amount of HD textures and high number of polygons in Halo 3, that is quite a feat.
The way the Bungie developers accomplished such small replay files was by only tracking (and saving) game code of everything happening in the game. Rather than saving the footage as a video file this allows the new viewer (the person you sent the replay) to move the camera around and zoom in and out. If the Smash Bros team uses a similar strategy for a game with no HD and a small environment you could easily get a three minute replay in under 40Mb file size.
To add to this, Sakurai has noted that we can save created levels, screenshots, and replays directly to an SD card. If the above tactic doesn't work, you still really don't need a harddrive.
Will there be an Adventure Mode creation tool?
The president of Nintendo of America recently told a media outlet during an interview that he wishes LittleBigPlanet was on the Wii and not on the PS3. In this game people create single-player levels from scratch and allow others to play through the level. My question with this Smash Bros update is whether or not you will be able to create single-player levels as well as Brawl stages. One thing I found interesting was a screenshot on the site with a ladder as an object option.
I have never once seen a ladder used in the way Mario is using that ladder in a Smash Bros game. In the middle of a Smash Brawl I think it would be awfully weird to stop the action and start climbing a ladder. So what could this mean for the create-a-level option? Perhaps a single-player level editor is on the horizon. One can only hope.
There are a few other things I have worries or suspicions about in regards to Smash Bros online features but that will have to wait until a later date. Not to say I don't love all these online features, because I absolutely do, I'm just saying there's more to it than what we know right now.