To start, you need to know what the official, confirmed requirements for playing AC: Unity are. Here is the official specifications page. Here's the summary.
Minimum System Requirements
OS: Windows 7 64-bit
CPU: Intel Core i5-2500K 3.3 GHz or AMD Athlon FX-8350 4.0 GHz
RAM: 6GB System Memory
GPU RAM: 2GB Graphics Memory
GPU: Nvidia GeForce GTX 680 or AMD Radeon HD 7970
HDD: 50GB Free Hard Drive Space
DX: DirectX 11
Audio: DX 9.0c Compatible Sound Card
Online: 256 kbps upload bandwidth or higher
Recommended System Requirements
OS: Windows 7 64-bit
CPU: Intel Core i7-3770 3.4 GHz or AMD FX-8350 4.0 GHz
RAM: 8 GB System Memory
GPU RAM: 3GB Graphics Memory
GPU: Nvidia GeForce GTX 780 or AMD Radeon R9 290X
I am not an AMD user. I've been Intel and Nvidia for a very long time. So I am only going to concern myself with those two manufacturers. Let's look at the CPU requirement first. There is only one way I am going to look at this. When was the recommended processor released? I believe looking at performance graphs, etc. is not necessary because it's a valid assumption that newer hardware will be more capable compared to previous hardware. Performance graphs are therefore not needed to determine if Ubisoft's required specifications are abnormal.
So when was the Intel Core i5-2500k 3.3 Ghz central processor released? According to Intel, this specific processor was released first quarter of 2011. That was almost four years ago. So you need to ask yourself, is that unreasonable for a minimum requirement processor. I don't think so. But, to be more object we should look at some minimum requirements for other games. The hard part about this will be in choosing games that are of the same genre and level of sophistication as AC: Unity. That's tough. I'm going to cheat a bit. I'm going to us AC4: Black Flag as the comparison because it's the predecessor to AC: Unity. That cements the same genre, same level of capability. If AC4: Black Flag's minimum required processor was and end of life model that was almost four years old when the game was released, we'll have a nice comparison point I think.
The minimum recommended Intel processor for AC4: Black Flag was an Intel Core2Quad Q8400 according to Steam. The launch date for that processor was second quarter of 2009. Ubisoft released AC4: Black Flag October 29, 2013. The Q8400 at that time was just over four years old. With hardware of that age, the difference between the i5-2500k and Q8400 from a capability point of view is negligible, but yes, the AC: Unity recommended minimum processor is about 6 months younger than the recommended minimum for AC4: Black Flag when it released. However, having an end of life recommended minimum processor is not extraordinary.
Now let's look at the graphics processor. The GPU probably has more to do with the performance of a game than the central processor. If Ubisoft's requirements are going to be unrealistic, I believe it is here that we'll see it. So, using the same reasoning as with the CPU, when was the GTX 680 released? Well, unlike Intel, Nvidia doesn't seem to have a nice easy reference site. However, going out to their product page and looking at some of the reviews they have linked, all the reviews were written in March of 2012. Assuming the reviews were written just before product release, we can safely assume the GTX 680 came on the market the second quarter of 2012. That was two and a half years ago. That's a bit newer than the CPU, but it's still a fairly old card - especially considering how hot the graphics processor market runs these days. Yes, that pun was intended. XD
So how does that stack up with the AC4: Black Flag GPU requirement. According to Steam, AC4: Black Flag required as a minimum a Nvidia Geforce GTX 260. Unfortuantely Nvidia does not have product reviews linked for legacy GPUs. It's a bit more difficult to get a release date from the proverbial horse's mouth, i.e. the manufacturer. So I went looking at secondary sources. I found a six-year-old Engadget review for the 200 series GPUs which I'll take for gospel. The GTX 260 came on the market in second quarter of 2008. In this instance, there is a significant difference between AC: Unity and AC4: Black Flag. The recommended minimum for AC4: Black Flag was over five years old when the game released. That is an 18 month difference between GPU minimums for the two games. But is that unrealistic?
Obviously many think it is. But is it really? Perhaps we should look at some recent game releases and see where they fall. Middle-earth: Shadow of Mordor requires a minimum GTX 460. In fact, its recommended card is a GTX 660 - less than AC: Unity's minimum. Now, I've not played Shadow of Mordor, but I've seen it played on YouTube. The graphics are comparable to AC4: Black Flag, but not nearly what AC: Unity offers. It's that upgraded experience which is purportedly driving the increased GPU requirement, and the requirement is substantively increased in AC: Unity. It does actually verge on the extraordinary.
Should Ubisoft have decreased the PC graphics capability in order to lower the recommended minimum? That's an interesting question, and it depends more on economics I think than software programming. There is an argument to be made that people who cannot afford a GTX 680 upgrade will probably own a console and not a gaming PC. If that assumption is true, the low-end market does not belong to the PC. It belongs to the Playstation and Xbox brands. If you lower the graphics requirement, you might get a few more people to buy the PC version of the game, but would it compare favorably to how many people will buy the game if the Apple business model is used instead?
I know, you think I've gone completely off the reservation here. But I haven't. Apple products go for a premium price. And they get it. Why? Because their devices are sleek, and elegant and a beautiful thing to hold in your hands. People pay the extra money to own such a well designed piece of technology. When it comes to a computer game, that all equates to how the game looks and performs. If it is both gorgeous and runs at 60 frames per second, you have the equivalent of an iPad. You can charge a premium price. That's why Shadow of Mordor sells for $49.99 and AC: Unity sells for $59.99. You know, I probably wouldn't pay $59.99 for a game if the graphics weren't drop-dead beautiful. I know I haven't bought Shadow of Mordor because I think the price is too high. I'll wait for a sell thank you very much.
But the Apple comparison really is a stretch, and I don't think that's what is going on here. Ubisoft may have changed their GPU age requirement for reasons completely unrelated to the game, though it's still related to economics and not video quality. A GTX 680 may cost $490, but it's a cinch to drop into your system board. The GTX 780 is even cheaper at $429.99. But what's more, there may be another dynamic going on here. Yesterday Nvidia posted this announcement. That's right, if you buy a new GTX GPU you can get AC: Unity free from participating retailers and PC builders. And all the biggies are included: Amazon, Newegg, EVGA, MSI, Cyberpower PC and a dozen more. Just in time for the holidays. Is that collusion I smell? :o Did Nvidia secretly subsidize Ubisoft to increase the graphics requirements? Now there's something to talk about.