I whole-heartedly agree.

There is no reason that an agency should take 80% of the profits.

Here are some ideas to get you started:

1. I believe that you would need to gather a consortium of submitters with large portfolios to make a difference.  If you could get a few dozen members with over 1000 images that would be a good start.

Once some of the larger submitters joined, many smaller submitters would fall in line and join.

2. The consortium would need to wield their power against smaller agencies first.  This would strike fear into the hearts of the larger agencies.  You don't want to pick on an agency that is too small, because you might put it out of business.  But you also don't want to start on a large agency, because if your first attempt fails, then people might disband.

For example, I would start with Fotolia first.  They have some of the worst royalties in the business.  Not only is the royalty percentage low (@ 33%), but their average payouts are small as well.  For me, they average 0.49/image (if you don't include Extended License sales).

Their Extended Licenses are also among the lowest in the business ($6.60), and there are no limits to their licenses (i.e., they allow unlimited runs).

3. IMO, the best way to "strike" would be to stop uploading for a while (such as a month).  This would drop sales at the agency, since many buyers sort by Newest Images.  The drop in sales would gain the attention of the agencies real fast.

Anyway, those are some of my thoughts.  Any feedback is welcome...

Unfortunately I dont think it would make a difference.  Even if you got the big names to join, why would anyone else?  Remove the big names and it will be more downloads for me?

Unionism really only works on an all or nothing basis. (ie when unions strike, they normally try to stop other non union members from going to work)

i think this same discussion went on when people started submitting to the micros as apposed to the macros.

And went on even earlier when royalty free images came about as apposed to rights managed.

Yes...of course you could always just start your own stock site.....Start with the 'technical' costs...servers etc, then realise the administration alone would mean you'd have to hire employees. To compete at all you'd have to market your site, both to clients and submitters. Ok, so now you have at least ten employees,office rent,computer and server costs...
You see where this is going? You could always of course just have a small site...But then the income would be...hmmm...about as much as you'd make from the existant micros.
The BEST model for any photog,once they have sufficient catalog, is to simply have their own site, for their own work, and directly market themselves to design firms et al. Of course this would take a lot of your time and effort,and you won't be spending as much time shooting.

It won't matter squat. iStock depends heavily and bases their model upon the exclusive photographers. In fact in the last year alone the share of exclusive photographer photos on the site risen twofold. They have higher upload limits (MUCH higher) get priority reviews, free business cards and most importantly to them: get commissions in order of 25-40% vs the 20% that everyone else gets. There is NO CHANCE IN HELL that any of the key photogs on iStock (and there is a lot of them: LiseGagne, Hidesy, Abu, Aldra, Mammamart, sx70...) would support this as they get a fairer share of profits. And none of our action will matter squat.

All Top 10 on iStock are exclusives and only 8 of all Diamond (> 25,000 sales) photogs are NON-exlusives. So I'm afraid this action is as futile as spitting at the sun to put it out.