HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

However, there won't be anyone saying, "I want to play without art glitches, cloning bugs, AI freezes, but with peeking and a buggy quick cast."!

Let me try to compare the quick cast bug with other bugs using specific examples.
The quote mentions 5 bugs. Let's assume I'm trying to convince my opponent to use version 3.0 and play with all options enabled. Then:
- I don't need to tell him about the art glitch bug; using it is pure cheating and prohibited by all the rules I know;
- I don't need to tell him about the cloning bug; if it doesn't happen, no one will notice (I barely know what this bug is; cloning is not often used in online games);
- I don't need to warn him about the absence of freezes;
- I don't need to warn him about the absence of peeking; I think it's clear why;
- there's still a whole list of bugs that I don't need to inform my opponent about.
But I definitely need to tell him about the improved quick cast, and not just tell him, but convince him that the old quick cast, which he's used to, is a bug, and the new one is the real deal. If I forget to tell him and he loses in a game, it will be my fault. If I tell him but can't convince him, we'll play without the new quick cast and without some other useful features.
That's what I call a difference.
And what is all this for? For fixing a bug that rarely occurs in a real game, has little impact on the game, and is familiar to everyone, and many don't even consider it a bug.