I like [planetary weapons] because their function is obvious, there is no need to constantly avoid selecting the defensive contingent, when grabbing fleets for attack. Once placed, i know that planet has protection no mater what happens to my fleets.
When I refer to "planet(ary) weapons", I mean anything attached to the planet that is a weapon (does damage, rather then protecting against damage), be it orbital or not.
Assuming there are planetary defense meters that are dependent on factors such as colony development level and which take time to grow to their max value, planetary weapons don't really eliminate this need, in general. Planet weapons could do so for a particular system / planet that is highly developed and well-defended by its weapons and (presumably) shield alone... However, many planets won't be sufficiently self-defended to be able to leave unprotected by fleets, which means that the player has to check each system when decided whether and how much to leave defensive fleets to augment that particular system's own defenses.
In all but brand-new colonies, it's reasonable to assume and require that whatever planet weapons and defenses are available would be enough to prevent just any piddly enemy ship from single-handedly destroying everything in the system. Having this wouldn't require actual weapons on the planets though, as long as the planets' defenses (eg. shields) are sufficient to stop trivial bombardment by enemy fleets.
However if we want to have any sort of blockading of systems, in which an enemy fleet is present and stops an incoming and outgoing physical resource transfers, then we likely need a few things:
* Shields strong enough that it's probably for there to be situations where one empire has enough fleet strength to hold a system and blockade it, but not enough fleet strength to actually break through the shield to capture the planet.
* Limited range planet weapons, or none at all, so that it's possible to have a fleet in a system without it being in range of the hostile planet's weapons. This has two advantages:
1) As suggested, it prevents hostile planets in the same system from having a meaningless battle against eachother each turn
2) Similarly, it lets a blockading fleet be in a system with a weapon-encrusted planet without actually battling the planet every turn.
Ensuring #2 might be tricky if we have meter-based planet weapons, as likely the blockading fleet will want to elminate the weapons attached to the planet. If we have no way of depeting these meters outside of a battle, then there will be motivating to have an essentially trivial battle each turn. Also: I don't like the idea of abstracted such battle, so that every few turns the blockader randomly loses a ship to to planet's weapons. Conversely, if there are no planet weapons to eliminate, then we don't have to worry about how to eliminate them every turn.
Alternatively, we could stipulate that planet's don't regenerate their weapons turn-by-turn if an enemy empire controls space in a system. To control a system (allowing blockade), you'd need to eliminate all enemy planets' weapons.
I'm also a bit weary of needing to compare fleet strength with planet weapon strength if the two are measured in sufficiently different ways. A meter value doesn't compare well to a mixed bunch of ships in a fleet, and I don't think we can really generate a comparison-ready single fleet strength value for the fleet...
...any destroyed orbitals decrease the current value planetary defensive weapons meter. And would be rebuilt, up to the currently possible max at the same rate they were originally built.
I agree that it's very problematic to try to cram [planet weapons and defenses] into a single meter. That's why i proposed
shields and weapons should have separate
meters, and that there be no trans-atmospheric missile bases.
It seems a bit excessively to have two (or more?) meters for planet defense; we shouldn't add more meters than absolutely necessary. That said, I'm leaning towards seeing it as justified.
...defensive orbitals would be the "special buildings" that the player builds on some key locations within his/hers empire to strengthen the defensive readiness...
Why not just build ships and station them where needed? Why do we need a separate class of buildable item to do this?
...how these orbitals could be special [:] much bigger [or] a lot smaller than ships, but you could build many of them...
Them being bigger or smaller doesn't mean anything right now, as it doesn't imply a strategic distinction to justify their existance.
Now without the planetary weapons/orbitals this kind of a system would mean that if there is no enemy fleet in an enemy system you could just send a huge fleet of troop transports to the system, land your ground troops and probably take control of the whole system.
You might have trouble doing this if the planet you were trying to attack had lots of ground troops to defend. And regardless, your suggestion has the orbitals being at the few rare special planets... so most planets would have only minor defenses and thus would be vulnerable to large fleets in either case... unless the defensive player left fleets there to protect the system.
...if your fleets are fighting against a powerful enemy on one side of your empire, your neighbours could just declare war to you and take control of a large number of your star systems with “a troop transport blitzkrieg” on the other side of the empire before your fleets could react to the problem.
As above, if you have all your forces away from a border, it's vulnerable regardless of what sort of defenses are possible, unless those defenses are excessively strong.
In addition, one good reason for having planetary weapons/orbitals could be that they give the player/ the AI a change to move their fleets around more freely, since your planets can defend themselves from some enemy attacks.
As noted, even if there are no planetary weapons, the presence of a shield that can stop trivial attacks does this.
And if there are no planetary weapons and orbitals there is the question of, How do we explain this to the player? Why he/she is unable to build weapons on his/her planets, which produce the resources for the empire, house the population and take a considerable amount of his/hers time to be managed?
This is a realism argument, however I'll humour you: Ships are built a shipyards, which are specialized facilities that just every planet doesn't have. Planets can contribute to the empire pool of industry to help build the ships, but they are actually assembled at the shipyard. So, you can build powerful spaceweapons at shipyards, but not anywhere else.
Well I see that there currently is a defense orbital in the game and see no reason for removing things similar to it from the player build able items.
We need to justify adding something, not the other way around. That it's present as a temporary feature of a previous design for a system that wasn't yet being seriously designed doesn't have any importance to me.