Well the good thing about sharing profits equally among members is that a large alliance with many many members will mean each player player gets less naq, because your alliance will only produce a certain amount that will have to be shared.
I do agree that you might get alliance bullying. If it is a major issue, there is always the possiblity of limiting alliance size, but thinking about it that still wont stop the bigger alliances stealing all the small alliances' naq hmm...
Thanks slep, you got me thinking
Edit: Ok my intial thoughts on the matter...
Make alliance warfare have a fairly hefty turns cost, so it isnt worth picking off the smaller alliances. This could also be used to curb large alliances a bit, by saying to attack another alliance, you need 15 turns/member (and maybe in -1 turns per member in the opposing alliance - with a minimum limit of course).
Any other ideas?
Edit 2: I just remember another idea from another thread...we could set an attack range, where you can only attack alliances either with half your alliance's naq or more.