Gotten further into Den-O and I think the final form for Ryotaro, the Liner form, is probably the best culmination of the idea of where I imagined this series was going. Ryotaro, the unlucky man with basically no presence becomes possessed by 5 beings who personify extreme versions of personalities he could embody, and through their constant interaction he builds the strength and presence to stand on his own.
Liner form is that personified as while in all his other forms he is kind of just a puppet playing on the strings of the Imagin possessing him, Liner form forces him into the driver seat. This actually makes his final form weaker then most of the previous forms he's had initially since Ryotaro isn't a strong fighter, but it symbolically shows how he's grown in strength as it gives him the capability to stand on his own, supported by his friends.
Looks wise it's alright but I think Den-O is definitely a rider that nailed it's best designed with the first it showed off and everything else just doesn't match up to it.