>>5696299i think its a combination of things;
they kept the fidelity of the models which is a nice touch cos i think people would've been pissed if it was just Vice city with a GTA V skin, but they have upped the polycounts on these a touch so it looks smoother.
Part of what made the GTA games what they were was this adaptation to the promotional 2D art they used into 3D by necessity of graphical limitations, the angular sharp character models were playing to this strength they had of using 'exagerrated realism' which was pretty much cartoonish up until GTA V, even IV had extremely exaggerated facial features on characters.
I think the problem here ultimately lies on their use of textures and post-processing effects/rendering, it looks like an ENB mod at times, and you can even see in the trailer they didn't really intend to capture the same ambience in lighting and atmosphere. The bloom and brightness is so cranked it makes the already smoothed out character models look REALLY smooth, and kinda sucks the life out of the picture.
For example; GTA 3 had this very 'early morning fog' feel to it, mostly driven by a small draw distance, and they took that out because that limitation no longer exists but kinda kills the vibe in the process. All in all, I think its a pretty lazy remastering, even in OP's pic Tommy's hair looks like plastic and his skin has no detail as opposed to
>>5696302 which has all kinds of details even at such low resolution on his face to give character and age.