The S5 would work well at 4 or 5 feet from the wall, no issue. They are more flexible of placement than the Alexia, and like most good speaker designs, if you can increase distance to 6-8 feet they will image even better. The Alexia will need to be nearer to back wall as their frequency response drops below 60Hz, you need to have the reinforcement of the back wall on the bass
What makes you believe that a cheap Scan Speak paper woofers and silk dome tweeter, a 30$ SB acoustics midrange, ferrite coils and Solen polypropylene in an overdamped Phenolic resin box will give a better speaker? the power of brands like Wilson always amazed me.... your post sounds a bit like post rationalization ;-)
On cabinet technology, see this interesting chart:
View attachment 12548
On tweeter: Berrylium tweeter of S5 gives you higher extension and much lower distortion than silk dome. Less distortion means it sounds sweeter, while having at the same time higher transparency.
On paper woofers: if you would see the level of distortion at 100dB you would laugh! place a bet: 20%? 30%?
on Mid-range: nothing bests the stiffness to weight ratio of the carbon fiber nano-tube structure of the S5. Which means again lower distortion and faster driver. Same for neodymium magnet: much more expensive but more linear magnetic field, lower distortion.
On XO: suggest you open your Alexia, replace the ferrite coils with the Mundorf oxygen-free copper foil of the S5, and the Solen polypropylene caps with the Mundorf Silver and gold and oil capacitors (also of the S5): you would be SHOCKED how much more transparent the Alexia would sound. I played a lot with XO when I was trying to improve my own speakers for fun long time ago: I have done the test. So why is Wilson not doing it? because it makes more sense for them to spend a lot of money in a nice spray painting (visible to consumers) than in parts that 90% of consumers don't think of, and using better components like the S5 would increase cost of the XO by a factor 7 to 10...
Truth is that the S5 is at $29.4k a real bargain - no wonder that the waiting list is getting longer. People interested should get one before year end, I wouldn't be surprised that Magico increases its price next year now that they have launched the S3.