I like it but i don't think gonna have a new brand military-themed sentai due the fact this theme is not exactly popular among the Sentai fandom in Japan.

Hmm true

But do you have any hypothetical ideas for their mechas, villains, gadgets/equipments/weapons and vehicles like motorcycles ?

I was thinking military-ish vehicles for the rangers like a helicopter, a fighter jet, a jeep car and so on. For the villains it would mostly be based on animals. I was thinking that the main villain would have an octopus head, like Tekken 7 Yoshimitsu but I have yet to come up with a name.

ok I'd want a mythological beast team but another European based one like Changeman

Ooh that would be pretty cool actually. Especially since the Changemen mecha is still based on millitary stuff, it would be cool to finally see mechas based on actual European mythological creatures, that’s for sure.

Of course why don't I think before I want mythological beast sentai theme like they did changeman

exactly(Goseiger KINDA did this but really only had red and pink be themed after such)(Red is going to be either Dragon or Phoenix that's just what it is)

I was wondering, would be interesting to see space ninjas from another planet just like the Aquitians in Sentai.

that sounds interesting. The closest we can get so far is Jakanja I guess... I just feel that the ninja theme is overdone tho, maybe something new or reuse a rarely used theme for the next Sentai?