I only played siege once since the new score formula, didn't really pay enough attention to it - maybe some of these mechanisms are in place already? Will check it out if I get the chance. A bonus near flag could work although it would be a shame to punish defenders for holding points of strategic importance that AREN'T in the vicinity of the flag - if the score (and thus multi, eventually) is to be gained simply by fighting near the flag, well, it sounds a lot like some sort of an xp barn to me, something I believe the devs are trying to avoid. I think something more contextual would be better, but again, I'm not sure of what's in place currently.