[vetinari]

Your point 4 has quite a problem with incentives alignment. You expect the SaaS vendor to spend resources in order to minimize your payment to them - their revenues. I can see why that would be somewhere among the lowest priorities.

Also, point 6. I understand where you come from, but you should also understand, that you are using release shared by several/many customers. If everyone had a veto power over rollout, nothing would get rolled out, at all. Therefore, if something gets broken, use your SLA, it is much easier to fix a specific bug, than delay the release.

[rini17]

On contrary, if there's no anxiety over unused accounts, clients might more easily buy larger plans.

[vetinari]

With point 1), I agree.

Point 4, depends on granularity. If it was on user/month basis ala GApps, then it might be workable.