Of course you are free to prefer what you like! But with all due respect, what I said isn't an empty argument at all, but the conclusion of what every programmer and game developer who were vocal on this topic have said, including Shafer himself! Again, how much more evidence do you need that with current understanding and abilities it is not possible to program a decent AI with this system? This is not about opinion.
By comparing the two systems I merely showed that the one system has a lot more potential (despite its flaws in Civ 4), because it can be improved on and fine-tuned, while Civ 5's system has the hard cap of a bad AI.
There are many other arguments in favour of stacking of course too, but this one is the most objectively quantifyable and really is indisputable.
I'm sorry, but you're simply wrong when you say that the AI can't handle 1 UpT.