Stockfish 8 openings

That doesn't add any variety if it still plays the same thing every time. The point is that on any move, it almost never varies its reply.

Well, in Russia we say that stability is the sign of a master. Even GMs tend to stick with their tried and true weapons so, maybe, we should take the SF example as a worthy role model.

No GM in the world replies to every move with the same move every game. If that was the case, the same game would be played over and over again. You can prepare almost an entire game against the engine with little effort. That's a sign of weakness, not mastery.

Ok, for example: Kasparov = Sicilian and Roy Lopez, Fischer - the same + 1.e4 99% of the time, Karpov = Karo-Kann, Morozevitsch = Ancient Gambits and so on. Each GM has some speciality. Carlsen, for instance, tends to avoid Indian systems. As for the weakness, how many times have you beaten the SF 8 level? Not many, I guess. Try to prepare a win against it, it would be enjoyable to watch.

Untrue, none of the GMs you mentioned played their pet systems literally 99% of the times. The engine does. Carlsen is the worst example you could possibly give in this discussion, he plays tons of openings. Also you clearly have no read what I wrote because this is not about move one but many moves to follow. And yes, I can easily use my own stockfish to prepare against the engine and get at least a good position out of the opening, the point is not that I will win against the engine because of its opening choices but that every game will be the same which is boring and completely unneccessary. A few lines of code will allow the engine to play different openings, which is obviously the right thing and what people want when they play against anyone or anything on any chess website.

Try to shake the SF as hard as you can, the lines of code will jumble and mingle and here it is: an absolutely new move, fresh and brisk, right off the stove!

If I were to be serious I'd ask just why don't you try any other engine, like Deep Junior, it's real creative and versatile.

I'm not talking about creativity here, I'm talking about very basic opening variety, which is as simple as one randomized variable, or use of an opening book. Any installed engine has the option to use a book and will play a variety of openings, based on its parameters. My regular stockfish on default settings will play many different lines in e4, d4 and even c4 and nf3 sometimes. Lichess's SF seems to play without an opening book and programmed to always play the top choice at its set depth/think time, which is preset by the difficulty setting, which means that it is highly likely for the engine to always play the same move in the same position. This can be easily fixed by giving it access to a book for the first couple moves and have it choose semi-randomly between good alternatives or, if playing without book, randomize the first moves and allow it to play its second and third-choice moves, which, as long as the evaluation is not drastically lower, will be all good and probably theory moves in the opening.

I guess I got it. Variety, wide range of different decent moves played by the engine that makes your gameplay more exciting. Alright.

My personal view is that by playing the same kind of openings move-to-move you allow yourself to understand them in great depth. It's like learning to perfectly speak one language instead of stuttering in three or four languages. It can help you to build your opening repertoire on solid and firm foundations. I personaly even MAKE my training-engine Fritz 9 to play THE SAME moves and I find it immersely useful.

And, by the way, SF play isn't that dry at all. It doesn't play the same move in the same position over and over again, if you take the SF's move back and try again, SF will respond differently (2 alternative moves guaranteed). I know it for sure from my own experience of playing against much-hated-by-me SF 8. All of those moves are real the best of the best in the given position and the best moves aren't ever numerous that's why they're the best. Even my Fritz 9 can't beat SF 8 (drawing it only).
I guess that's because SF 8 chooses the BEST moves (of which there are 2 or 3 at best).