Honestly... they kind of were that bad. It's not about how they compare to later 3D, but to earlier 2D. Old 2D point & clicks still mostly look really good. The 3D ones... not so much. Just compare Monkey Island 4 with any of the previous in the series. It doesn't have a leg to stand on.

The person I quoted didn't compare it to anything. I don't think it looks terrible when compared to e.g. Quake (whatever version). However, I liked the look of GK1 a lot more.

Gabriel Knight 3 visuals were good... back then. Today? Nope. And I always wanted to replay it, but every time I installed and launched it I couldn't stand looking for more than 60sec. And don't get me started about the possibly worst control scheme ever in an adventure game.
Gabriel Knight 1 is a masterpiece, even by today's standards.

For me that's Grim Fandango (without mouse mod). And even with the mouse mod, some parts didn't work without using the keyboard.

True, the original Grim Fandango controls needed a bit to get used to. The not-fun part was that you had to make Manny run everywhere to discover where he turns his head. I haven't played the remaster, but I believe it should be a lot easier as a point 'n click game.

But Gabriel Knight 3... It always felt like detaching Gabriel's head, making it fly around - even in very remote areas - and then decide where Gabriel should actually go.