Okay, bear with me for a sec cos this might sound a bit odd
Reading the thread about CTF gave me an idea, how about add more victory conditions? One could be allowing alliances to build Wonders.
It would work as follows:
Each planet may only build 1 Wonder, the planet must also be a paid planet.
The Wonder takes 10 times as long to build as any other Structure. So for Terrans it takes 100 ticks, etc... Changing your Engineering priorities DOES NOT affect the amount of time it takes to build a Wonder, it always takes the maximum x 10.
While you are building a Wonder you may not build any other Structures. You may cancel the production of your Wonder at any time.
Once built the Wonder takes up 1 Structure slot.
Once built the Universe is informed of the Wonder's creation. This can either be in the form of an in-game Mail telling each planet the coordinates of the Wonder or if we want to be more sneaky about it it can just appear on the Universe page.
Once the Universe has been informed the Wonder is vulnerable for a certain period of time. This can be 12 ticks, 24 ticks, 72 ticks, whatever is thought to be suitable.
During this time the Wonder can be destroyed. It can only be destroyed by the use of Structure Killers, covert opping doesn't work. The Wonder is just as likely to be destroyed as any other Structure. So if 10% of your Structures are destroyed there is a 10% chance that your Wonder will be destroyed.
After the vulnerable period is over the Wonder is invincible, it cannot be destroyed by covert opping or Structure Killers. The Wonder then remains at the planet until the end of the Round, taking up 1 Structure slot.
You may not start building a wonder until a suitable number of ticks have passed. This will give people time to build up their roiding fleets and Structure Killers.
Each Alliance may only have one vulnerable Wonder at a time. Any other Wonders belonging to the Alliance that are in production during this time are put on hold. Perhaps a good idea would be to continue putting these on hold for a period after the vulnerability is over. This will make it so that an Alliance does not constantly have vulnerable Structures.
If a planet with a Wonder leaves the Alliance at any time then the Wonder remains on that planet but the point for the Wonder remains with the Alliance that built it. If the planet leaves while the Wonder is vulnerable then the Wonder is destroyed and must be rebuilt from scratch.
The Alliance that wins the Wonder victory is the Alliance with the most Wonders at the end of the Round. This will favour Alliances with lots of members so perhaps a better solution would be that the first Alliance to build 20 Wonders wins. This means that the Wonder victory will be over before the Round ends, allowing Alliances to concentrate on CTF and the Score victory.
The Alliance that wins the Wonder victory gets credits, 5 or whatever. Of course there is still the Score victory and CTF victory up for grabs too, the fact that you win the Wonder victory has no bearing on how well you do in the other two.
The one major problem I see with implementing this is that Structure Killers will become more prolific seeing as there is now a purpose to them. The way to solve this is to make the use of Structure Killers more tactical. My favourite suggestion at the moment is
this one which suggests changing the class of the Structure Killers. This means that you will either have to team up with another race to shield your Structure Killers or send off-class ships to protect them. This will make the use of Structure Killers more focussed to missions such as these rather than just having people bung them in with their roiders because they can.