Aston Martin's "flavor" is very heavy in the Fusion, and I agree with a lot of what you said. They also took the opportunity to begin investing in the midsized market long before the other 2 of the 3. Ford has had the Taurus for decades and it has done well... their current run started with the Fiesta in the early 2000s (basically a crap compact... but that's all compacts were at the time), then began making the Focus and 500... all around 2006 (well before the economy tanked). The 500 was basically a transition model for Ford to redo it's Taurus... which is now competitive with the Maxima as a larger, sportier sedan that offers a standard V6. The Fusion then came out of the wake of the 500 and has done real well... and will continue to get better. I'm sure Ford is working on a CVT transmission for the Fusion because that's the only thing that is really holding it back right now. Currently, A 4 cyl. Fusion can muster 32-33 on the highway while an Accord, Camry, or Altima can get up to 20% better. In the midsized segment, you better be able to match or beat the market leader in fuel economy to be competitive. Those numbers carry a lot of weight.
I feel German cars are slipping in reliability, especially Mercedes. Most people I know who drive new, German-made cars have issues with them... and you can't just take them down to the local shop to have them repaired. Most places in Starkville will hardly change the oil on a Mercedes or VW, much less work on one. You are limited to the dealership... and you better be ready to have a lot of cash if you are paying out of pocket. German-made cars are still good cars... a lot of prestige... but Mercedes has lost it's way some in terms of overall reliability. They still have the brand image they want, but reliability and cost of maintenance will hurt the German-made cars soon enough.
Way back in the day, Mercedes did a fabulous job engineering and designing their cars... along with offering great, detailed maintenance manuals. There was nothing at all flashy about them, but they were the longest lasting, best built cars on the road in any country. The older cars were a gear-head or weekend hobbyist's dreams because they were very easy to work on. They were built that way because Mercedes marketed to the German working-man who may not have had access to a shop to get their car worked on, so they set up a distribution network for parts and provided them with manuals. Now, you can't open the hood of a Mercedes or VW without specialized equipment because in the US, they are seen as a more prestigious car. I guess if you can afford own a Mercedes, you can afford to have it worked on.