The website does show a screenshot of the form change system and Ghost will at least be able to transform from Ore to Toucon Boost and stay in that respective form. He also has 2 finishers, one for Mugen and on for Greatful so I don't know what's up with that (Probably like you were able to unlock finishers in RiGen 2)
two finisher might prolly be like the Ghost Eshop games, one that is weak and one that is stronger(Kick and Omedama for Ghost at that time)
I believe Gaim, Baron and Ryugen will have form changes for their base forms. Gaim had permanent ones in Senki (Pine and Ichigo, with Wizard being an unlock exclusive). The final forms were never playable in RiGen anyways, so it's fine by me.
Zangetsu Shin and Suika Zangetsu is already confirmed as one-off special attacks(Shin also becomes finisher too), no permanent form change to Zangetsu Shin, and most likely because they don't want to bother making too many special moves for the original Zangetsu's moveset and just use transformation specials to fill up the remaining special move slot
Ryugen's Kiwi and Yomotsuheguri arms are one off special moves too since they revert back to Ryugen after attacking, and i'm not talking about finishers, just regular specials
i don't think Wizard Arms will be making a return in the game
I must disagree, I think they are doing a great job with the limited ressources they are given. I was always very fond of the RiGen series, they always were able to make me want to play as every single Rider. I wonder who will be the secret 18th Rider (probably Snipe)
i never realy liked Rider Generation, choppy animations aside, the gameplay is so unbalanced since they treated the showa as generic and crap, which makes the whole "a lot of riders playable" becoming useless because the only ones worth playing were the heisei ones and maybe 3 of the Showas, in Battride, baring the DLC characters everyone is just as great "full" even if the characters did not have transformations and whatnot
for example: Baron in Genesis, that was really impressive, and they even managed to do stuffs with G3-X that i didn't have thought they will do that far....the showas are also way more colorful and enjoyable than the RG version(except Super 1 and Skyrider, both version of games have their own unique charm, the other Showas tho, Battride wins by a far stretch)
if there's one thing i liked in the RG games is that sometimes they have better version of finisher attacks than Battride War/Climax heroes, like Fourze Cosmic's Cho Ginga Finish in RG2, Delta's finisher, or Gaim Kiwami's Gate of Helheim finisher attack, also they have team finishers that are not generic Double Rider Kick, Battride should really implement that too.
as for characters, i bet it's Gold Drive, since every evil rider-class boss featured before had become playable