Nintendo has recently been re-publishing older interviews (many of which were never previously translated into English) on a variety of topics, and one of them contained a rather interesting look into the development of Super Mario Bros. 3. The recently-released Wii U game Paper Mario: Color Splash features a Super Mario Bros. 3 inspired level with an overhead view, and as it turns out, this was actually Nintendo's original plan for the classic NES game. Shigeru Miyamoto and Takashi Tezuka experimented with a top-down style during development, but they couldn't quite get it right.
What sorts of things did you have trouble getting right?
Tezuka: When we first began development, we wanted the game to have an overhead perspective, rather than a horizontal one.
So instead of having a horizontal view of the game like in Super Mario Bros, you wanted something like an isometric view.
Tezuka: That's right. But, we just couldn't make it work.
Miyamoto: He said "I want the game to be viewed from a little bit above." But having a clear indication of where you're going to land after jumping was a key part of the original Super Mario. Viewing everything from above made it very difficult to tell how far you were from the ground, so I told Mr. Tezuka "This will take forever."
Tezuka: …He did (dry laugh). In fact, there are still remnants of the top-down view in the final game, from before we switched to the horizontal view…
Miyamoto: Yes, there are.
For example, things like the black and white checkered floor?
Tezuka: That's right.
While they ended up ditching the idea (or one of the most iconic games in history would have been quite different), it's interesting that the idea lives on in Color Splash.