I'll have to agree with @RejZoR on this one. This isn't as bad as I thought. The two major cons of this build are unplugged power cord from GPU and the single channel RAM. The power cord situation speaks for itself - for us it's easy to fix, but good luck to a person who bought it as his/her first PC. Terrible, but I suspect it was just a bad luck. The single stick of RAM is really a stupid decision. Since this is designed to be used by people who have no idea about the technical side of PCs, I don't think they will be upgrading RAM anytime soon, so there's no point in leaving that second DDR4 slot empty. It would be MUCH better if they put 2x8GB inside. This is probably the reason for these FPS drops. PSU is a no-name brand, which is a bit bad, but as long as the lines are powerful enough, it should work fine, especially without overclocking and so on.
As for the rest, I don't see anything bad with it. The motherboard is cheap, well of course it is. I also pick the absolutely cheapest one for my builds, since I'm not overclocking and I've always used non-K CPUs. If you're going on a budget, then ~60 USD motherboard is all you need. I'm running on one for years and there's nothing wrong with it. It's a good way to save money. I'm planning on moving from i5-4440 / MSI B85M-P33 combo and I will most likely buy i7-8700 with a cheapest MSI / AsRock. Lack of USB 3.0 on front panel... well, I don't find it necessary. As long as there are USB 3.0 ports on the back of PC, it's fine. Keep in mind that it's all about cutting the costs whenever possible to offer the lowest price. For many people there REALLY is a BIG difference between 1100 and 1250 USD, and putting better motherboard, better case and better PSU would most likely increase the price by that margin.
One thing that I don't understand, though, is... why Walmart? Why pre-built PCs in the first place? I'm not from US, I'm from Poland, so I never understood the appeal and popularity of these products. When big electronic markets started to become popular in Poland in the late 90s / early 2000s, they also tried to sell such prebuilt PCs, but it never really worked here. People always went to more PC-oriented shops, either local or online. These days every single online shop with PC parts has an option for you to check "Please, assemble my PC" after you've picked your parts. Usually, it's either free or costs something like 50-80 PLN (20 USD?). They also offer prebuilt PCs, but it's not like these are treated as "one product" with some weird name. These are usually sample rigs built from the most popular products, so you get exactly the same thing as you would have if you built the PC by yourself. Where does the appeal for CyberPower PC, HP Omen and all these pre-built rigs come from? It barely exists here, in Poland.