if you didn't like risen 1 you're not gonna like gothic. risen 1 is basically just gothic with updated graphics
it's nothing like da or bg
Risen 1 is really good, as well.
And yes, Risen 1 is extremely similar to Gothic 1 - small isolated area/island; lots of quests; lots of decisions to make; siding w/ certain factions can shape both your character + their class. If you loved Gothic 1, Risen 1 will feel like PB's best game since Gothic 1.
Though, Risen 1 isn't anywhere as difficult as Gothic 1+2. It's still difficult, mind you - but it's still a bit more friendly than Gothic 1+2, in some ways. Risen 1's combat does improve over previous PB games - as it utilizes mouse-look, unlike Gothic 1+2. It's a bit tighter than Gothic 3 with its camera-movement, though - Gothic 3 was much looser.
Risen 2+3 are quite different from Risen 1, as those games are better suited for a gamepad. B/c of the game having an unlocked camera by default, you can actually easier attack multiple enemies from any direction - which is better suited for a gamepad. But, if you played Risen 1, you will have a huge curve of getting used to this mechanic...or not, since a lot of people hated this change. Using your right mouse button for holding it to stay locked and unlocking the camera by not holding it - that can take some getting used to it, if you can actually get used to it. Personally, I prefer the gamepad on Risen 2+3 - feels like this game was designed more so around this (especially since Risen 2+3 were also on consoles; and since Risen 1 on consoles was a technical disaster).
I love Risen 2 with its pirate setting, as they absolutely nailed it. Though, they basically threw normal magic out the window + replaced it w/ voodoo magic in Risen 2. While voodoo magic is cool and all, they shouldn't never throw the regular magic out the window! Risen 2 really didn't have battles on ships that you could control, though - unlike Risen 3. Risen 2 felt like a lot of its choices and decisions didn't matter in shaping your experience, character + the outcome of the game - meanwhile Risen 3 brought back a lot of that classic Gothic 1+2 decision-making stuff + questing that made the series what it is.
Risen 3 rehashes, remixes, and re-uses a lot of Risen 2 areas, characters, and other assets - which does make Risen 3 feel more so like an expansion than say a true-blue sequel. Risen 3 also brought regular magic back to the table. Risen 3 might feel like it perfected the Risen 2 formula, tweaked the Risen 2 formula + improved over Risen 2's issues - but it still feels more like an expansion than sequel; and doesn't feel anywhere as fresh as Risen 2.