Rocktopus is one of those instances of a good idea by devs that they ruined by fearing it becoming overpowered and thus nerfing it into garbage (ironic considering how blatantly OP other things in the game are). It is too slow baseline to be useable (even with teleport sats) and its range is so short even cities without rocket batteries can knock one down if you place it close enough to be able to hit the city itself.
To make it *barely* useable you need to select one of its weakness eliminations (don't take the can de-orbit at will). The move bonus will let it follow your army around and will be great for taking out enemy sats as well as providing coverage for your own (don't send it up). The coverage bonus supposedly lets it shoot further when it is in orbit which makes it good for city siege.
Yes it is severely limited even with the upgrade. It needs to be brought up to 2 move and have +1 range when in orbit baseline to be worth using.
Well luckily it can be buffed in a patch, like all other balance issues. Although why would you even bother with a Rocktopus when you can get Orbital Lasers? I mean other then perhaps being more accessible to Harmony players because it's closer to all the other Harmony techs I don't really see the point in it.
Upgraded Rocktopus's orbital attack is stronger than the laser but not the Planet Carver.
To make Rocktopus useful here is what I would do:
Base move increased to 2.
Range of orbital attack increased by 1.
Orbital coverage upgrade perk replaced with enhanced miasma spreading speed when in orbit. This new perk should be the Harmony or Evolved upgrade. Switch as necessary.
Voila, Rocktopus is useful.
Well luckily it can be buffed in a patch, like all other balance issues. Although why would you even bother with a Rocktopus when you can get Orbital Lasers? I mean other then perhaps being more accessible to Harmony players because it's closer to all the other Harmony techs I don't really see the point in it.