Just Dance 3/Beta Elements

Dancers

 * A duet with a male and a female was planned to be in the game. The male is wearing a jacket with a button up shirt with a bowtie. The female is wearing what looks like something Lady Gaga would wear. The unknown duet is featured on the PAL version cover. People unofficially dubbed that it maybe Alejandro by Lady Gaga or it resembles Crazy Little Thing Called Love.
 * Jungle Drum by Emiliana Torrini was planned to be in the game as the 50th song but her song was taken out before the release of the game for reasons unknown. The choreography seems to be done, however, it appears in the Puppet Master Modes of Ain't No Other Man, Super Bass and some other ones on Just Dance 4. The dancer is wearing a leaf dress, has gone barefoot, has blue hair with a flower in it and a light blue glove, if you look at the video on URL in part 3:09 3:15, you will see a part of choreo that probably is not in puppet master.
 * A solo female dancer appears in mashups in Just Dance 3 and 4 but it's unknown what song she was supposed to be in. The dancer has pink hair in pigtails, a purple crop top, a pink skirt, purple leggings, and pink shoes. People unofficially dubbed as an original or Alternate version of Baby One More Time, or maybe it's a dancer created just for the Mashup, because Ubisoft didn't find anything better that could fit the rhythm. She appears in the mashup of the song people most believe she was supposed to be in.
 * Also, the coaches were going to land their jumps instead of freezing in the midair.
 * In the Best Buy Edition, there is a beta picture of Barbra Streisand, with a different color scheme and longer hair. Also, on the NTSC cover, she has a different color scheme, too.
 * On the PAL cover of Just Dance 3, Pump It has a different color scheme.
 * In the first trailer, Gonna Make You Sweat (Everybody Dance Now) had a more greenish color.
 * The Dynamite coaches had a different colour scheme.
 * The background of Kurio ko uddah le jana looked more crooked than in the final version.
 * The coaches of No Limit had different positions, with the male as P1 and the female as P2.
 * The Teenage Dream background in the chorus was different: it was darker, with more balloons and smoother lights.
 * P2 from Crazy Little Thing Called Love had a different haircut.

Choreographies

 * The choreography for the chorus of What You Waiting For? looked completely different in the final game. The original choreo was first seen in the early announcement of Just Dance 3. The color schemes had some changes too.
 * A theory could be that the original choreography did not have too many moves to be counted on Wii and PS3, if you count the moves of the chorus, you'll realize there will be only like 6 counted moves for punctuation, instead of more than 20 counted moves in the final one, meaning that the original choreography may have been impossible to get 5 stars on for such consoles.
 * Gonna Make You Sweat (Everybody Dance Now) has a Mash-Up that is only available if Just Dance 3 was preordered from GameStop for the Xbox 360. Some people have done this but weren't able to get the mashup.
 * Airplanes has 4 unused Gold Moves.
 * Boom had a different background, as seen in a trailer on Vimeo. It was blue with white spotted lights. Also, a Beta pictogram appears in Just Dance Now files.
 * Lollipop, Take On Me, Hungarian Dance No. 5, Soul Searchin', Pump It, I'm So Excited and the remake of Funplex have Beta pictograms.
 * In the Just Dance Now files for I Was Made For Lovin' You, a single pictogram that seems to portray P2 is seen.
 * If you look into the NTSC manual for Just Dance 3, you can notice that Lollipop and Think's places in the menu were switched, meaning that they were originally in different places before the worldwide release.
 * Tightrope has an unfinished pictogram.
 * Let's Go To The Mall has 2 placeholder pictograms, that show the no GUI gameplay with some drawn arrows to finalize the Gold Moves.

DLCs

 * Some of the Xbox 360 exclusive DLCs (such as Funplex, Mashed Potato Time, Heart Of Glass etc.) were meant to be available on the Wii version as a DLC as well, as there are some unused Just Dance 3 menu icons which can be found in the Just Dance Now files. Additionally, it was announced that Heart Of Glass was going to be available on the Wii version of the game as a DLC, although this never happened.
 * On PAL manual, there's Jamaican Dance in the DLC menu

Interface

 * Lyrics and the pictograms were originally going to be in the middle.
 * In the Beta version, the graphics looked different in all consoles.
 * On Xbox, the players' names were written in a different font and the motion cam had a white outline.
 * Duet pictograms were going to slide from different sides, like in Just Dance 2; in fact, if you explore the Just Dance Now files of No Limit and Baby Zouk, you can notice that the original pictograms are separated.
 * The pictograms on Wii and PS3 were going to disappear with the same fading effect as in the Xbox 360 version, as you can see in this video.