I hate multi-boxing, and thus am unaware of how effective such a technique would or wouldn't be. I know it's not difficult resource wise for the computer, since it's such an old game, but running 6 toons around? Or logging them on/off all the time... grouping them all the time. I dunno, for me that's just not fun. In any case, you may be right and someone would do that. So that's good enough reason for a change.
But this still leaves the spirit of my post unanswered, which is basically, how do group bonuses work? All I know right now, as a TT, is that if I am in a group I get some percentage increase in sales, period. This benefits anyone also in the station, in my group. But is it a fixed increase? Does it change with level? With Trade Level? Is it based at all on the Negotiate skill?
Since it is obvious that at least part of the way it works is different from live, it does suggest the possibility that it has been changed in other ways. And this suggests the possibility that group bonuses as a whole have been altered as well.
As far as I can tell, there's nothing on the forums describing how they work in practice now.