Is this meant as a ROM Hack idea, or mostly a suggestion for the series? If the latter, then it might be better off elsewhere by now, where it would also gain more relevant attention.
When it comes to FR/LG, 're-making' them might be a bit complex, as they aren't necessarily counted as independent releases. In addition, R/B/Y were recently released for a different platform, not as a re-make per se, but nonetheless sufficiently to perhaps dissuade immediately reprising those releases. In addition, they do have other games with Mega-Evolutions, etc., without having to add this to the earlier releases, so they should be fine. Of course, there are many ROM Hacks of FR/LG which already involve extra evolutions and so on, so in that sense it might also be a fairly well-tread ground by itself. Fans of the newer games might prefer those in any case, and as such not need the earlier games ported over further times.
Still, if you do intend for a ROM Hack idea by that post, you might want to specify a bit. While it could be done, 3DS hacking is at a fairly basic stage and it would often mostly be a map reshuffle and so on.