Multi-GPU trade-offs

Since PCI-Express and it's remarkable flexibility made a debut in the computer world, much has changed among graphical subsystem solutions - one of the key words today is scalability.

With the introduction of the new CrossFire X technology AMD will be able to supply solutions based on 2, 3 and 4 GPUs running together, with the aim of supplying the fastest graphics subsystem to users and OEMs everywhere. This is what multi-GPU solutions are all about: providing the highest possible performance with each hardware generation.
While this is true for benchmarking because it does break records and helps manufacturers show their technological superiority, but what about actual benefits, without trade-offs?

The problem with embracing these solutions is that most people are actually also embracing the possibility of making their gaming experience worse. This happens by the means of the added processing overhead, associated with the increased processing power required to handle synchronization and load balancing(in case of split frame rendering), resulting in lower framerate in worst case scenarios.
Two good examples of this are the reviews to the CrossFireX technology from HardOCP and PCPerspective; take also the HD 3870X2 review from Xbitlabs.

They show a general increase in maximum framerate but decreases in the minimum framerate - which is something both AMD and Nvidia should be focusing in increasing, at least for the sake of customer satisfaction.
I am citing illustrative examples, some games perform better, some worse; some are worse with three GPUs, some with four. It's a driver issue and will probably be worse with a slower CPU, unable to balance or synchronize the graphics cards properly. While I admit that a very fast processor is the way to go before considering this approach to increase performance, at which point is the CPU able to cope with both the added overhead, increased focus on processing more realistic physics and artificial intelligence? A big chunk starts missing from the processing power you had before.

Drivers are the most important part of a multi-GPU solution and will provide good performance improvements if done right, the problem is that's not the case most of the time. Most of the drivers provided require specific optimizations for a given game or they will perform worse or the same.
We also have the problem known as micro-stutter, a consequence of all these problems. From research, these problems are inherited from the use of AFR(alternate frame rendering) instead of the use SFR, the far better approach to solving the problem, yet far more difficult to implement, which sometimes gets lost along the way.

Ever since their introduction I've actually praised Multi-GPU solutions because, in theory, they offer a good way to upgrade your graphics system without throwing your existing one "to the trash can". This was assuming that all caveats were dealt with, which is something that hasn't been happening for a long time.
At which point, after spending so much money to get the best of the best, do you have to start doing your own benchmarks to check if you're really getting your money is worth or if you would just been better off with one graphics card?
In situations where large monitors and resolutions come into play, a multi-GPU solution is probably worth the extra investment, at least to have decent framerates most of the time, but it is still questionable.
A place where multi-GPU solutions will shine is when GPU physics come into play. Not using two graphics cards to render will actually decrease the overhead and with the GPU helping out with physics calculations it will surely help in the most processing-bound situations, therefore delivering a better gaming experience.

Since we as users have already lost much of the control we had on our computers by relying too much on the providers AMD and Nvidia and their drivers, has the PC gaming industry lost it's biggest call? Today we are almost almost forced to buy a multi-GPU solution to get the best of the best. When will every PC gamer just get sick and tired of this whole game and move to greener, console, pastures? That day has been farther away.