They want to build interest in the sequel while also squeezing out the last bit of money from the first one. At $10 it's a steal and many who missed out on this game earlier or had problems with the DRM will jump at the opportunity. I for one am certainly significantly more interested in the sequel now that I have played more than the demo of the original.

Well I know what the publisher's motivations are, of course. I wonder what GoG's motivations are, as it's the least likely candidate to be called old on the entire site.
I am not taking issue with it being here either. As I said, I just bought the GoG release and am glad that there's a drm-free flavor. I am just curious to know what GoG's motivation is to post it here. Not the publisher's, but GoG's.

Let's see... Getting money to pay employees and releasing more games?

Also, both CD Projekt (GOG.com) and Reality Pump (Two Worlds) are Polish, so I think there is some pride and maybe personal friendships playing into this one :-)

As Penny Arcade observed fairly recently, genres are a crude tool for describing games these days anyway. You call it what you like. It's certainly true that there's little or no role-playing involved.
I consider that one of its strengths though. It doesn't muck around with anything it doesn't need to, and each gameplay element that remains is honed to perfection. There's basically nothing between you and playing the game.

Definitions vary. Anything not new can be called old.

I like PA but I don't rely on them for my choice of game to play or for my taste in general. Never have never will. If you (and anyone else) likes DIablo, then good for you. We don't actually disagree on anything. I just refuse to call this arcade game an RPG or compare any RPG to it for RPG elements.

I linked to them because that particular main page has some interesting observations on game genres, and how dated a tool they are.

As someone that spent about 6 hours I am enjoying this game. Never heard it before but I have now and will definitely look at the sequel.
I like how 'alive' the world is, which I didn't get in Oblivion.
Can't say why but it feels like 'yes that village man I left 20mins ago is still doing X without me there'.

There's always a need for genres, games are too broad a field to not have them. There's not much a Madden NFL and Diablo have in common, or a business simulation and an abstract arcade shooter. Games might mix and match play-mechanical or thematic concepts, or introduce new elements that come to define genres in their own right, but there can be found sensible taxonomies. I never thought much of the "we're beyond genres" attitude some sites have - they simply are the most powerful way in which people can narrow in their areas of interest (in terms of, when looking for the title of a game on MobyGames, genre is one of the first filters you will set).

Diablo and Two Worlds are most absolutely RPGs. The term has absolutely nothing to do with roleplaying - it is simply a transfer of RPG mechanics from tabletop to PC.
I.e.
Characters have numerical stats to describe their profficiencies and defficencies
Characters can choose a class to specialise in, opening up one or more skill trees
As characters become stronger (level) they accrue points to spend on their numerical stats and to invest in new skills
Every character, whether player-controlled or not, has its own set of numerical data and skills
Every time conflict occurs the stats of the opposing entities are compared to see in which areas each side triumphs. Normally a dice is rolled to introduce a small element of luck into the equation. These comparisons and rolls are used in any conflict, not just in combat. You want to open that door? Your lockpicking skill and associated stats better be to a level that will give you a good chance against the complexity of that lock.
That's what RPG means in terms of gaming. It's got nothing to do with storytelling or strong characterisation in the slightest. Just as you can play tabletop without getting into character, you can play a RPG videogame without a need to act. Most games bar FPSs have an element of RPG mechanics under the hood, although these are often hidden from the player. When they are exposed and the player is able to see and manipulate this numerical data, the game is labelled RPG.
All that aside, Diablo and Diablo II go further and don't simply borrow the mechanics from RPG, they are literally computer representations of a tabletop game. Dungeon crawiling is tabletop RPG. If you find a lack of RPG in the Diablo series, then I don't know where you will find it in a computer game.

If the bugs have been sorted out, then I might get this. Avoided it on PC up to now due to the DRM, and some bad press. But if the issues are sorted, I could do with another open world RPG to add to my collection.

Great timing considering Two Worlds 2 is in the making. : )

I'm pretty sure most if not all the bugs are gone.

I can second that, I completed the game in v1.7 twice without any crash or memory leak or bug (at least none that I would still remember). And the load times are, considering the size of the world, some of the quickest I've seen. I came to consider as one of the most stable and tidily programmed games of the last few years I've played, long before I found out that the game owed a lot of its bad reputation to the bugs in the release version. No doubt players should demand games to be in good state from day one, but at least they went through with fixing what was broken (which is more than you can say about many other developers)