Will probably comment on other developments later...but Oorotto's design looks cool (a little reminiscent of the Digimon Cherrymon and Woodmon (moreso Cherrymon), although I'd imagine that all 'tree-based' fictional monsters will look similar to another at one point or another). It also seems like a dreadful thing to encounter in hordes within a forested area... :<
My hopes are that it's a Grass/Ghost type (or maybe Grass/Dark; something part Grass-type, at least, not another Sudowoodo typing-betrays-design ordeal), with a possible English name of Rotroot or Bruteroot (1st Pokemon movie's novelization's nicknames FTW).
Additionally, giving it the Ability Flash Fire would be a bit interesting, as it would nullify the common weakness of Fire and would likely surprise/dash the hopes of Trainers who were planning on taking it on with a Fire-type Pokemon. (I haven't seen Fennekin's recent trailer with Oorotto yet, but if a Fire-type is used, Flash Fire can still be saved for a potential 2nd or 3rd/Hidden Ability). ^^