While playing a 3DS game, did you think there was some sort of missed opportunity? For Me (Final Fantasy X spoiler incoming):

Kingdom Hearts: Dream Drop Distance - Being that the game has this whole dream theme (where the worlds are "dreaming"), I thought it would be a perfect time to introduce a Final Fantasy world, Zanarkand (the "sleeping" version summoned up by Yu Yevon in FFX).

Since KH has never been canon to any of the FF games, they could have messed around a bit, and included Tidas, Auron, & Jecht together (three characters known to have been in Zanarkand in FFX). By clearing out the Dream Eaters & finding the world's sleeping keyhole, it would reveal that Sora/Riku, while not fully waking the world, have set it up to be awakened, and that would have to wait "for another story" (a slight nod to FFX's story).

Of course, they already have alternate versions of Tidus, Auron, Yuna, Rikku, and Wakka in KH, but if you've played DDD, you'd be well aware that the sleeping worlds play by their own rules (two different versions of Mickey are present within the sleeping worlds, in addition to the real one). Also, this would have been the perfect excuse to have Seymour as a hidden optional boss (seeing as how KH isn't canon to any FF anyways).

Kid Icarus: Uprising - The campaign, weapons system and extras were fantastic, but the multiplayer could've been so much more.. Only 10/12 maps (2 were friend exclusive) and the randomized matches were quite barebones. Plus another game mode like Capture the Flag or Regular Team Battle would've been nice. I really wish this game was updated with more content.

Resident Evil: Revelations - The achievements system was like a cruel joke. Seriously, that thing was a disgrace. I also wish they added some sort of competitive multiplayer but Raid Mode was good enough with friends (random online sucks)

VVVVVV - Level editor. Seriously wtf, why the hell would you charge more for a version with less content?

Crush3D - Should've been a sequel

• I would have loved it if Uprising were a FPS with the controls present in the DS's FPS games for land battles while sticking to its current on-rails design for air battles.
• New Super Mario Brothers 2 should have had more difficulty modes for its single player that rewarded the player with more coins than normal, and Coin Rush should have never had a limit.
• Super Mario 3D Land should have used the Koopalings as world bosses for the special worlds.
• Mario Kart 7 should have had a single player VS mode.
• Resident Evil Revelations should have found someway to just allow Jill to be controllable in its single player, as she is in the game's demo. That game is mostly a mess in terms of story.
• Pushmo and Crashmo should've made the elder a super guide. Have him walk up onto the Pushmo platform when the player is taking a while to solve a puzzle.

SSFIV AE DLC
Pilotwings resort a NintendoLand like plaza for MIIs to gather via flight

I'm still sad that 3D Land has nothing to do with the gameboy games and NSMB2 has nothing to do with Super Mario Bros. 2.

Disney Epic Mickey: Power of Illusion should've been much longer. With all the characters from various classic films in the game, the game would've been so much better if Mickey could've went to illusions of all of their worlds instead of just three of them.

There's many things that could've made New Super Mario Bros. 2 better, but it should've had a new soundtrack and Wario.

The first isn't a missed opportunity, that would require complete change.
And the second is subjective, but the 4 options were of great variety (I was satisfied with my Circle Pad Pro). And the atrocious story... Well, I liked the camp factor, but I'm gonna agree anyways because I think they attempted to be serious.

Considering the multiplayer was tacked on, added last minute, it's pretty darn good and I'm fine with what we got.

Them making a TPS for land battles instead of FPS is a missed oppurtunity to me, and yes, it likely would require quite a bit of change.

Well, the entire post is subjective, and I believe you misunderstood me as I'm not talking about control options. I actually enjoy the controls for Revelations and how they were executed. My problem is being thrown into the roles of these different characters, rather than just focusing on playing and gaining the story through Jill's perspective.

Pac-Man & Galaga Dimensions should've had Streetpass for scores and TATE mode for the original arcade games, I still enjoy it though.

Super Mario 3D Land as a whole. Pleasedonthatemeijustfounditsortofdisappointing. I was hoping it would be more like Galaxy, but instead it ended up being... Sort of weird. I mean, it's got a speed running asset sort of like the old Crash games did, but... For some reason the whole thing fell flat from what it should have been to me.

Mario Kart 7: Biggest missed opportunity was not including a single player vs mode, any kind of single player mission/tournament mode or time trial leaderboards. All would have helped the game enormously.

New Super Mario Bros 2: Could have been a great game with more original elements like an all new soundtrack and Wario.

Love Plus could have used some English subtitles.

This is more "opportunity that MIGHT be missed" that "opportunity that WAS missed," but...

http://www.project-phoenix.deviantart.com/journal/Not-sure-if...

...I can not help but agree with the second paragraph of the Journal entry here.

(EDIT: I add this: http://comments.deviantart.com/1/304826063/2894581233 )

Mario Kart 7
I see it as a missed opportunity as a whole. Submarine and "flying" sections don't add anything, the courses' designs are not very good, no missions, not enough characters, battle mode is still worse than MK64's...
I was dissapointed, I expected a lot from this game but it didn't deliver.

Mario
Both platformers are good but New feels recycled and Land lacks that magic that could be found in previous 3d Marios. They are., again, missed opportunities. Just not at the same level as MK7 (thank gods)
A level editor for NSMB2 would have been awesome and could work wonderfully with street pass.

The graphics complaint for X and Y is moot at the moment since we're looking at blown-up images from the game and it's still nine months away.

A few others have already mentioned it, but I still think having Wario as the villain of NSMB2 was a big missed opportunity. It would not only have made the game feel "newer" than having to defeat Bowser again, but it just seems logical that Wario would be involved since collecting as many coins as possible was a major theme.

Then having the option to play through the game as Wario with a different move set would have been incredible. It was fairly short to begin with, so this feature would have been great for replayability...especially for those who aren't into Coin Rush Mode.

Pilotwings - Should have had either DLC for extra challenges or online multiplayer for 4 - 8 people. Enjoyed what was there immensely, but it's way too short.

Star Fox 64 - Online multiplayer!

Dillon's Rolling Western - An alternate control scheme.

Steel Diver: More of the adventure/time trial mode. What's already there is excellent

Colors!3D: Let's see... Custom sized canvas, more brush options, "recently used colours" button, tags for image uploading, fill tool, gradient tool, magic lasso (ok, I'll admit that one's a bit too demanding), Masking, Pixel Art mode, straight line tool, circle/ellipse/other basic shapes tool, select+move tool...

I agree!
Really, it should have been called NSMB 3 , that makes sense for many reasons; the "2" makes no logical sense no matter how you look at it.