This is something I've found recently that, when I'm online, I'll be lucky to be on for 1 besieged, or by the time it has finished preparing I'll have to do something else, go to bed, go to work, w/e.
The problem being, it is the best source for imperial standing right now and I've been wanting to upgrade Salvage pieces since I'm confused the Devs are going to eventually 119 Salvage stuff and to upgrade I'm having to just burn through my copper vouchers.
So what I suggest is that the beastmen armies need to prepare and reach Whitegate a lot quicker so we end up having between 5-10 besieged daily, we're so strong compared to besieged mobs now that we kill them in 5mins so it shouldn't really matter that besieged is more frequent.
Anyway I'd love to get feedback, maybe people agree with me, or disagree but I'd love to find out.