The post is not about evoking deep emotions, it is about having a deep emotional goal behind its creation.
Still, your comments are interesting and valid. It is very interesting if games can really evoke the full spectrum of emotions that we have in books and movies. When it comes to mimicking human expressions I do not see this as a large obstacle because 1) animated movies can be just as sucessful as one with live actors and 2) tech like the one used in Benjamin Button is that not that far from possible real-time. So we either have or will soon have the tools to imitate characters with deep emotions.
But your main point is really if the protagonist, ie the player, can be made into feeling emotions as the character, right? To take your example, can the player play the role of one of the lovers in a romantic drama? I find this very, very interesting and I see two ways this can be done:
1) By creating a situation where the player truly, by themselves, feel this emotion.
2) Forcing the emotion, by "fooling" (think hypnosis) the player that they are really having this emotion.
There is not a distinct lines between these two options, but I think it is well worth making anyway.
When it comes to 1, this is highly subjective as it would be very hard to satisfy most player's demands for a certain feeling / attachment. You would then have to have a pretty sophisticated system that can adapt to the player. I'd say that this would be very hard for certain things like love and so on.
Option number 2 though, I think is much more plausible. We know that people under hypnosis can be made to believe certain stuff (at least they will say afterwards that they DID feel this, which I think is enough when it comes to subjective experiences). Hypnosis, as far I as I been able to research (as in reading books,etc), is just a sort of play between people. I think it is possible to do something similar in videogames too and in this way convince players that they really do feel a certain way. While this might sound a little scary, it is not that far from what movies do. What happens is that emotions in other people trigger similar emotions in you. When watching a sad scene and sufficiently immersed, the feelings of the character pop up in yourself as well*. Books also work in a similar manner but bypassing the visual input and directing the input directly (through symbols).
By designing a video game in a proper way, the same kind of transfer should be possible to happen, using a mixture of the techniques in hypnosis and film/books. Basically a video game could basically "tell" the player that they are in love with another character and the player will accept this.
Of course this is just my hypothesis and I might be terribly be wrong. The only way to see if it might work is to try it out. We have already tried it out a bit in Amnesia with cues that tell the player when to be frightened (through music, visuals, etc). It is just some very early tests, and it has have so-so success, and we will try to evolve it, step by step and see what can and cannot be done. Only way to know what is possible
* See this as an example: http://www.youtube.com/watch?v=t0pwKzTRG5E