Ood, i think the opposite
you are a bit screwed if you want to craft a couple of K of something that takes hours
while you are crafting you can't help others run dungeons
ok you could participate in world chat but i don't go in there much
so i could go down the pub for 2 hours
or save it till the end of the day and stack it all up and go to bed
but people do "stop playing the game" while they are crafting
there is Bulk crafting on raw mats but i want my little alt to get the maximum XP so i never use that
i guess the reason you can't login twice on different alts is to stop botting, collaborating or trading between alts (although that would be nice)
so that is why i thought of logout and stay logged in
you could only do crafting on an alt that is 'logged out but in' and couldn't interact with your alt in any way
maybe not even allowed in the same building or area
but something would be helpful for levellers