I would like to see more of Viva Pinata since it was a pretty cute and funny show. However, as cohenmarioman mentioned, their original shows haven't done that well. TMNT lasted a lot longer than their other original shows, but it still didn't have the best merchandise sells or ratings.
Considering that they're airing the third season now, it does seem like getting the rest of Winx Club could be a possibility. Granted, they're airing it to fulfill the E/I requirements, but having more episodes could help them with that if they wanted to get more episodes. I also think that the VAs on that show are pretty good and it would be nice if they continued with the series.
I still think it would be really cool if they did finish up GX, especially since they left it on a terrible and misleading cliffhanger. Even so, I'm not sure how likely that is considering that they're focused on 5D's and they may want to work on new shows instead of old ones. Still, I would be completely happy if they made the choice to continue with the series.
I seriously doubt that they would dub the Toei Yu-Gi-Oh! series. It doesn't promote the card game nearly as much as DM, GX and 5D's does. There are some episodes that introduce the game, but there are more episodes focused on random games than Duel Monsters. I also don't think that it was really successful in Japan, which would explain why DM remade some of the events that the first series covered in a few flasrabroadacks instead of having the two series connected. I also remeraber hearing that Toei would not let the series go to be dubbed and there also might be a legal reason for that due to TV Tokyo and Konami dealing with the next series, but I'm not too sure about the details on that one. Still, I think that there are quite a few reasons preventing 4KiRAB from getting the first Yu-Gi-Oh! series.
I didn't know that. I thought that the same companies involved in the anime series were the same ones with the OVA. Thanks for clearing that up.