Even if "take 10" is removed, there needs to be some alternative for actions that are not really intended to be rolled - I am mostly looking a the military actions here. Having to roll for every move unit action and change status would be an administrative nightmare. So if the ability to take 10 is removed, some alternative should exist for those actions.
The problem, if I understand Bjørn right, is that the effective difference in cost between performing an action, fx a rule action at a (total) DDC of 10 and 11, is huge depending on whether you can take 10 or not. It's weird that it can cost you 2 GB to rule a holding at 100% success chance (ish, you never know if someone spends influence against you) and at the same time 12 GB for 95% success chance.
IMO the best solution to that is to simply remove the take 10 rule and make certain actions autosuccessful under certain circumstances. I think military actions should then be succesful if performed together with a wage war action. Administrative actions (fx changing taxes) should be successful if the province/realm is not in rebellion and so on.
Then just lower the DDC on some actions to make them easier to perform and you will be done, imo.
However, if the goal is to make it worthwhile to spend a little resources on a lot of different actions and not make it necessay/compelling to go for 2+ on so many... then something to make it less likely, that all the resources spent just disappear, is needed. Degrees of failure would be the obvious route for that. Andy's suggestion is very cool - changes the action dynamic somewhat, but could work.