I just finished Risen 2 & 3 run and must say despite the bad press these games get, I had a good time. Sure, both of them are inferior to Gothics in terms of combat and exploration. They however make up for some of it with the fun pirate setting, distinct style and hilarious dialogues (conversations with Patty and the gnomes always deliver).
Dark Waters have more of the sheer hilarity in badass dialogues (in Titan Lords most funny and dickish responses cost you part of your soul), I also liked combat a bit more - in 3 every human enemy or monster has this ridiculous jumping attack that you have to avoid by frantic dodges, which I did not enjoy at all. Besides, there is also no kick in 3. The story in 2 is also better - fighting Mara is a clear continuation of the struggle against the Titan Lords. Necroloth is revealed as a Titan Lord in the last chapters of 3, like it was an afterthought. The Shadows are lame and cliched opponents, I much prefered the sea monsters of 2.
However, character building in 2 is butchered by the fact that all the best stuff (lockpicking, dialogue options, monkeys, parrots, dirty tricks) is hidden under just one stat: cunning. Risen 3 distributed the goodness more equally between dexterity, influence, cunning, toughness and even made spirit a wortwhile choice (alchemy!). The faction system in 3 is better than in 2 but the problem is those factions rarely interact with each other and mostly don't have mutually exclusive agendas. Basically they all want to battle Shadows and only differ in methods.
Dark Watters have a better hero. If you have a nameless protagonist without a fixed backstory, who is basically avatar of the player, why change him between parts of the trilogy? Patty's previously unmentioned brother is an unneeded addition to the world that already has a heroic figure who saved it a couple of times and should have been given a chance to do it once more. Also, the voice actor of the PC in Titan Lords was obviously trying too hard. I prefered the relaxed no bullshit voice of the nameless hero from 2 to the edgy Batman-like voice of the nameless hero from 3.
Finally, the sea battles. Dark Waters completely dropped the ball here. If you want to make a pirate epic, some of it has to happen on the sea. In Risen 2 you only have like 2 lame battles with sea monsters in which you don't even get to steer, just shoot. Sea battles in Risen 3 are not perfect, but at least you get some maneuvering with your ship and several boarding actions. Still not great but better than nothing. It's a pity you cannot customize your ship in any Risen. At least in 3 you get to choose it's general looks (together with a faction).
All in all these are not bad games, just very flawed ones, hampered by obvious budget problems. The decline from earlier offerings of Pyranha Bytes is obvious, but they also tried to bring some fresh elements to the table. However I must say that being a pirate felt like real fun and in the end, that's what matters when it comes to games. Being a pirate felt so good than now I am continuing the experience, this time in Vendetta: Curse of the Raven's Cry. A game with even worse press, terrible score, but more developped pirate elements (customizable ships and crews, navigating the high seas, real naval battles, historical Carribean setting). I am definately intrigued.