It's proven time and time again that's more beneficial to tackle your competition head on, than shying away from it. See Samsung Vs Apple or Coors Vs Bud Light or Car A Vs Car B. You don't allow your competition to go unchecked if you have any desire to upstage their seating or compete. Soul Sacrifice was selected as the title most expected at TGS. It needs the marketing muscle to be successful, but it doesn't needs to sell more than MH4, it just needs to present the qualities that make it a viable alternative to it.
Firstly, your point was not simply to exploit competition success to make your own product successful, but more making useless comparisons to eventually steal userbase from Monster Hunter, because "graphically Vita can do better than 3DS in games of the genre you like the most". Indeed, Samsung smartphones have not damaged yet Apple's sales, they simply have enlarged the market. Secondly, I could have agreed with you if those games were on 3DS, but on Vita? Its low installed base is ridicoulous, and it won't be so much better in Spring 2013; the gap with 3DS will be bigger than ever, also. So, how can they exploit the success of a game which is on another platform, being games on a platform no one wants or cares (and one of them being also on PSP)?
Furthermore, yeah, it's reliable that the TGS most expected titles was Soul Sacrifice; who said that, Sony?
The differences in the titles lie beyond the fact that they have better graphics, if they care about having a friend to play, Soul Sacrifice will allow them to play with their friends online, which MH4 doesn't. It also has unique mechanics for the cooperative gameplay, thus Sony should focus on the strengths of their titles over MH. So yes they have qualities that can be marketed as a plus over MH4.
Monster Hunter 4 does have online.
But you can see how useless online is when Monster Hunter Portable 3rd didn't have that, and it sold almost 5 million units; and 3G is on its way to 1.6 million units with just the local co-op. Probably you don't know how big Monster Hunter is because of local multiplayer, just ask anyone who went in Japan wihen the latest PSP entry was released.
By the way, you talked just about graphical comparison, which is silly. If people actually cared about graphics, they would have bought Vita in the first place, and not 3DS.
As for other qualities over Monster Hunter 4, what are you talking about? Monster Hunter 4 has its own qualities as well, such as being the new entry in the series after 2 years and a half, having new gameplay dynamics, having new monsters, an actual plot, et cetera.
I mean, if Monster Hunter 4 and Soul Sacrifice were advertised toghether, the second one would only be the poor clone, the wannabe Monster Hunter.
The differences go beyond the technical aspects of software, there are features that are different and value added to the experience. If they are clones or not doesn't matter, everything is a remix and the key to creativity is just knowing how to effectively hide your sources, if the game has merits to stand by itself, being a clone won't be harmful to it.
Which features? Care to explain?
The most distinctive feature of Soul Sacrifice is the violence of its style and its grotesque abilities, something you can hardly advertised on TV; God Eater 2 has its own characteristics, but people know them since it's a proven IP.
Furthermore, being a clone may not be dangerous when the release occurs on the platform where the fanbase is (e.g. Phantasy Star Portable, God Eater), but probably the hunger of games on Vita will play a more important role in the commercial status of Soul Sacrifice.