Yu-Gi-Oh! series, I don't think that there has been that much fairness for people who have only watched the dub to begin with. I have my doubts that there are a lot of loyal longtime fans of the dub considering that the later DVD releases, especially for GX, were clearly doing so poorly that 4Kids didn't even bother trying to have DVDs for 5D's. Although, their really poor financial state didn't help them out in that regard either, but if there were a significant number of loyal fans of the dub, then the sales would have been better and they could have at least made some effort to get a DVD release for all of their dubbed episodes. The closest they got was with DM and despite being the only successful Yu-Gi-Oh! series, it still has an incomplete DVD release. At least the demand for uncut Yu-Gi-Oh! eventually led to the legal subs and possibly the inclusion the subbed version of the anniversary movie in the UK DVD release. I like Dan Green and I thought that he did a good job as Yugi, but I'm more than willing to see if another actor could do well in that role. At least he wouldn't be replaced during the show's production, unlike with the original cast of Pokemon, and depending on where the new company is located, he may not be able to get the role anyway. I just would like to see a more faithful dub of the past three series.
Another reason why I don't think that the 4Kids dubs would be released on DVD is due to GX and 5D's. Neither series actually has a sense of conclusion, although I'll give 4Kids credit with their attempt to provide some closure in their finale for 5D's, they didn't have good ratings and neither were that popular. The DM dub has the best chance to be re-released due to being the only successful Yu-Gi-Oh! series thus far, but even then I think it's more likely that they'll put them online instead. The new company wouldn't want to take the time and money necessary to re-release a series only to for it to tank. Given that the history of dub Yu-Gi-Oh! on DVD has, I doubt that the re-releases would actually sell well. I'm sure that whoever gets the license will release the anniversary movie and maybe the DM dub at best, but even then I have my doubts about the latter. When I mentioned about actually getting DVDs when this announcement first came up, I was thinking about DVDs for the current and future series, the anniversary movie and hopefully redubs at some point.
I know that making a redub would take much more money than re-release the dub and I don't know how many times I've said that I know it isn't too likely to happen, but I think that there is a larger audience for uncut Yu-Gi-Oh! than there is for the dubs. There were those few uncut DVD releases from a few years ago, which were only stopped due to the Japanese voice actor contract issues and raws of DM were uploaded 4Kids' YouTube Channel, which lead to them subbing 5D's, Zexal and the anniversary movie. The only way that the new company would be willing to redub the three previous series would be if they believed that there is a strong enough demand to warrant those costs and made them believe that they would get plenty of money back. I think that there is a demand for it and depending on who ends up with the license, I think that they could redub the last three series at some point, but that wouldn't be until after they get their own dub for Zexal up off the ground and get money off the ratings and merchandise for that series as well.
As for One Piece, many people would also say that the DM dub was horrible. I think it was their second worst dub. The main advantage it has over their One Piece dub was that DM was actually successful, although that probably would have been the case regardless of who dubbed it, if only for the card game. Personally, I thought that it was much more watchable with some effort put into the voice acting as well, but that's just me. Though, the One Piece dub gets much more hatred, which is why it was ignored after Funimation got the license, but given the success of the DM dub, it, along with the other 4Kids dubs, will probably be available legally online at some point.