-This post will be updated with new sentai rumors, as they come. Nothing here is confirmed, and so taking it with a big grain of salt is recommended.
So far we have:
-The new Sentai will appear in Goseiger VS Shinkenger. The new Sentai will be an anniversary type celebration show, like Decade for Sentai. The Cards will be used next year too, and past reds will show up in the new season, with as many old actors in tact as they can manage.
-A new "Key Item" will be marketed alongside the cards, much like the Headders were in Goseiger. Like the OOO medals, the key item might be usable with Dice-Oh
-It is rumored/suggested that Datas will stay behind on Earth when the Goseiger leave and assist the new team of heroes next year.
-Datas will gain a new form, the blue parts on him turning red. His voice actor will change. This change is rumored to happen in the team-up betwen Goseiger and Shinkenger.
-After transformation, the new rangers will utilize a new belt with disks. The disks will be of Dice-Oh compatability/design. The rangers will have a Badge on their left lapel, looking like SunVulcan. The disks will be usable with the henshin device.