I think the thread title is misleading, almost no one actually argues for planets to be invincible as long as stations are there or the orbit is not completely cleared.
What i meant when i agreed with OP in my first post without further elaborating at that time, was a.) the status quo is bad, and b.) i would prefer space control over the system present at that time(without the rather elegant - but insufficient imho - attempt with the tractor beams).
Ideal is neither of the two extremes, space control would just be less bad.
But i think there is a middle ground here, by allowing invasions without space control, but destroying or even better letting the original owner keep the stations/fleets. Stations would block the use of the planet for the invader, the troops would do the same for the original owner and i believe should also hamper the station in some way.
Enemy fleets of a vanquished empire could maybe rally somewhere and make an all out attempt at the enemy homeworld. Or they could become a new pirate faction with an intense hatred for you.
That is what i would like to see. Now let's look at what is.
With the tractor beams prioritising troop transports winning with such cheesy a tactic as "just breaking through with your handful of troop transports, who needs a fleet anyway" could become, if the AI includes enough of them, much much harder. That is good, it emphasises the importance of actual armed vessels and their battles.
Just handing over the station reduces the value of assault pods and makes attempting to take one not just a useless exercise, but actual harmful for the player.
Troops take planets, assault pods conquer ships and structures. But it is just not viable with the design at the moment, which is sad since it would add to the mix the decision to attempt to take it intact and not have to build one with the risk/cost of loosing a few more ships/equipping a few otherwise rather useless pods and reduce your strength.
This would even be a issue worth consideration if the station would just self destruct once the planet is captured.
At the moment, the winner of a land battle gets the planet, and on top of that the station intact.
If he manages to attack simultaneously all planets, which you could do even without declaring war just before the last command to the troop ships to fly to their targets from their rally points just outside his territory, he even gets the whole enemy fleet.
The war takes a month and gives the enemy almost no time to react.
So a already relatively powerful player gets a bunch of valuable planets, complete with stations, and an entire fleet that has not seen any combat worth mentioning.
That is a power comes to power just because of power situation, where the stronger side gets just too much gain for being already quite powerful in the first place.
Which makes it even more powerful.
The player/AI starts steamrolling, the game becomes boring.
This counteracts improvements in AI, from the developers and from AI-Mod, as it makes stations and fleets that you get handed on a silver platter even more valuable, since the AI actually has designs that are good.
It also nullifies to some extent the game concepts in place to support small empires and hinder big, already powerful ones.
Like the corruption mechanic, the research cap, the speed of hyperdrives designed so slow/fast as to emphasize the difficulty that comes with an increase in space to defend.
We are also actually discussing two issues. The first, flipping stations is to some extend already dealt with, although the verdict is still out as to how well.
The second is connected, but also separate, the effects of eliminating an empire.
That is already a quite rewarding event, getting bonuses from the race, income, a front less to worry and so on.
It is made even more profitable as need be with the victor getting handed over the enemy fleet.
This is unaddressed, and, i would argue, even more harmful for gameplay. It is bugging me more at any rate.
While the tractor beams now maybe make a suicide run of troop transports just not worth it in almost all cases, nothing short of denying the victor the fleet will make the latter problem go away. It is just too good a gain not to be worth almost any effort in sneaking in and not fighting the enemy armada as not to reduce your gain after the conquest.
Of course the player can just scrap the stations and fleets himself, but the need for houserule after houserule is a sad thing for any strategy game. And i would really like to have them still as enemies rather than just gone.