Simplify feature purchasing
Per all 365 tools, large institutions often have cumbersome purchase processes. Paying extra for individual little services is a pain the [bleep]. Thus, maybe allow ANY feature to be used, but those with an extra fee are so marked. There would be a pool of available "feature credits" included in the plan that one could tap into. If the pool grows empty, then throttling starts and perhaps non-intrusive notices. The throttling and notice frequency increases with "feature debt". It's not an all or nothing situation that can suddenly keep people getting work done, but a gradual and increasing nudge. Plus, it allows one to kick the tires of new features without administrative hassles.