I love colonial marines, the community is great and the developers are awesome, especially with the new content the regularly put out. I especially enjoy changes to the marines, with the introduction of def-con and an 'alternative endgame involving planetary nuke.
Which is why the Xenomorph endgame always irks me a little.
Xenomorph end game is bad for the Xeno morphs. Marine game play is good for the marines, defcon makes it easier to kill xenos the longer the game goes on. Killing xenos makes it easier to control the map. Defcon can even act as a comeback or alternative win condition for marines.
Let's look at xenomorph endgame.
If Xenomorphs attack the FoB, marines retreat the Almayer. Assaulting the Almayer leads to the marines being out on a timer to win or the round is a draw. Assaulting the Almayer forces you to face ERTs. Assaulting the Almayer forces you to face marine forces on their turf.
These are REALLY good reason NOT to attack the Almayer until you are at full strength. However, this takes time, no one wants to wait for Tier 3 xenos to reach Ancient, so admins force xenos to go up.
In other words Xenomorphs don't have an incentive to attack the Almayer, whilst marines are rewarded for remaining planet side and retreating.
I believe admins forcing Xenomorphs to attack the Almayer should never happen, Xenomorphs should be rewarded for moving the game forward.
Marines are not forced to leave FoBs, Xenomorphs should not be forced to leave the planet, game play should make them want to carry out these actions.
T;,dr:Give Xenomorphs an incentive to attack the Almayer and to a lesser extent, to do whatever it is the devs think we should be doing.