I kind of want to do a Matthewmatosis style review of this game and the series in general. The only issue being no way for me to capture 3DS footage. Emulator works for GBA and DS, and I have an Elgato.
Anyway, I had been thinking about this: Nintendo actually made the right decision with how they handled this localization, even though it seems half-assed and released without any marketing. If you look at the localization staff in the credits, this game was localized by 6 people. The series has historically had low sales in North America. They even marketed the DS game fairly well toward a wider audience, having a commercial with Beyonce in it. It still didn't move copies. Generating interest in this series has proven to be a difficult task for Nintendo. More buzz about the game spreads via word of mouth and the internet (like GAF).
Localizing these games isn't exactly an easy task either. Rather than a direct translation, for any voiced audio, syllables have to match the Japanese version. This can lead to some awkward translations, but often they have been handled pretty gracefully. An example of this is Cheer Readers, where one of the phrases in the Japanese version (hyphenated for syllables) is "Let's-u-ev-ery-bo-dy-go". This is understandable in English, but wouldn't be pronounced this way, nor make much sense, so it became "Let's-go-read-a-bunch-a-books". An entire endless game, Manzai, was cut from the English version of Rhythm Heaven Fever for this reason. On top of that, songs with lyrics have to be translated to fit syllables, and you have to get a singer to perform it on par with the Japanese version. In the DS games, they had an issue with getting a decent performance on some of the songs, and most of the players liked the Japanese audio better. The NA version of the DS game didn't have dual audio, so players were stuck with the English audio. In Fever, NoA still committed budget, and had much better vocals overall. However the game!e still did not sell.
This brings us to where we are now, with Megamix. It feels like NoA only brought the game over because of it's small but vocal fanbase. It's clear the localization budget was much lower this time, just look at Lush Remix to see evidence of that. Vocals from previous games were used where applicable, meaning the same dubs from the DS game were used for Fan Club amd the Dazzles. For voice cues, new voices were recorded, and aren't exactly great delivery, but get the job done (I'm looking at you Space Dance). Most of the fans of these games had their minds made up already: they like the Japanese lyrics and cues better. None of the games had dual audio until now. NoA seems to get that only a minority wants this game, and likely would have imported the Japanese version if the 3DS wasn't region locked. So Nintendo kept that audience in mind with the dual audio and minimal localization effort. No matter how well an English version of Lush Remix would have turned out, fans would still rather have the Japanese version. I like to call this approach to localization the "Tokyo Mirage Sessions approach". That game is keeping all the Japanese voices and singing, all with English subtitles, menus, etc. It makes sense given the audience of the game generally has no problem with Japanese lyrics or Japanese speaking characters in a game that is about Tokyo. Rhythm Heaven is the same situation, English is the default, but most of the fans will switch to Japanese audio.
While I wish we had a retail release, I'm glad we got the game at all, as I would guess there was a slim chance of it coming to NA in the first place.