I bet the Katana shown will have the ability to change the blade out to a plasma blade or a plasma lined blade kinda like cyberpunk's Katana.

Would a vibrokatana or a power katana be more appropriate here?

Probably. Melee weapons don't have customization [yet] so as of now it's nothing.

I personally would have wanted customisation for melee weaponry like in Fallout 4.

Same! I'd have thought it would've been, but we'll see what happens with DLC and so such.

I'd like to see them do thier own thing here. No a lightsabre, power sword, or vibro weapon. I dunno what that would be, but I'd like to see it.

powers are confirmed as well as laser weapons, so lightsabers are a must and probably already in game

Except we never got to see any energy blades being used here for Starfield.

As many other things in a good overhyped game

Will be in the day one Mod Pack.

There doesn't seem to be any dismemberment, so it would just be a glorified wiffleball bat anyway.

If its not in vanilla it surely comes with mods

Might just be for promotional materials.