It's another of those sloppy game mechanic ideas that is around some time now...don't take the time to balance the gameplay, just put enough CC in, to make battles last longer, and make people think the game is balanced because they live more than 2 seconds vs x class...original and evolutionary ideas at it's finest...
If they are divided instances that dont affect the player cap on the field then i can get behind it i guess, but ill still frown upon you all looking at the skies from my trench whilst you are having tea in space. The notion of the player cap came from the very early development where Patrick talked about their promise of 1000 player battles. He went about how they will see just how much their tech allows them to do. Thus a cap (no matter how small or big) will indeed exist, so anyone whos doing non war related things will indeed be taking a place of someone who wants to contribute to the war effort. But like i said if its instanced and confined to space ships there wont be an issue, none of that flower picking or mountain climbing in the world rife with war, ill shoot you myself if i see someone doing that.
Now, don't get me wrong, I'll be in the trench, fighting also, but some people like their downtime.So, if social areas are instanced, good for them, they can stay there as long as they like...
As far as social light hearted thing to enjoy, I think that your character can collect fragments of junk and bring them back to the their ship to be studied by the Adeptus Mechanicus. It would be the only use for collecting random crap. Sometimes, the techpriest will give you something in return: A fully sculpted 28mm model of an army of your choice. Unlike your character, the model can be from any army, and any color scheme you wish. You can have angry marines. Then, you can go over to your strike crusier's tech center and play "Wargames" against other players. Fun, simulated battles that train you to command troops at a level that may never be available to you - you may never get to be a Council Member - so here's a fun alternative.
It was obviously a figure of speech, as in someone will fight whilst others will slack. On that note though we know nothing of this planets history or anything, and IG fight trench warfare all the time so there are indeed trenches in 40k. SM/CSM will obviously not use them. For instance: http://1.bp.blogspot.com/_JOeFW2H1e...AAII/P7QNsClPfFA/s1600/Trench_War_Table_1.jpg
true.. but honestly, that 'marines dont need cover' shit is bullshit. space marines are overpowered in lore so much. its so inconsistent with..well everything. a lasgun is able to melt a crater the size of a childs fist into a shoulder pad. shouldn't take too many shots to take a marine down--cover does help with that. just...it pisses me off. some of 40k. it really pisses me off.