It is great, that classic Diablo is now on GOG.COM. But what about other Blizzard titles, such as 'WarCraft: Orcs and Humans' and 'WarCraft 2: Battle.net Edition'? Is there any chance, that we see them aswell?

Already officially confirmed. From Blizzard:

"Q: Are other classic Blizzard games coming to GOG.COM?
A: Yes! We have announced that we’re partnering with GOG.COM to release Warcraft: Orcs and Humans and Warcraft II. We’ll reveal more information at a later date."

Its been confirmed by Blizzard that they are coming to GOG. Officially no date has been given but rumor is that it could be next week.

"Q: Are other classic Blizzard games coming to GOG.COM?
A: Yes! We have announced that we’re partnering with GOG.COM to release Warcraft: Orcs and Humans and Warcraft II. We’ll reveal more information at a later date."

https://news.blizzard.com/diablo3/22887361/diablo-now-available-on-gog-com

Don't forget about Lost Vikings 2. (And might as well make the first one as well as Rock'n'Roll Racing, which are already free downloads @Blizzard, available here as well, if just for convenience.)

Lost Vikings 2 on PC?

Yep.

https://www.mobygames.com/game/dos/norse-by-norse-west-the-return-of-the-lost-vikings

https://www.mobygames.com/game/windows/norse-by-norse-west-the-return-of-the-lost-vikings

I mean, Journey is finally coming to PC and in addition, I might be able to play these classics without having to resort to piracy or overpriced CDs on eBay?

This year sounds very promising so far.

You made my day with those news!

The free Rock'n'Roll Racing from the Blizzard site is just a demo, not the full game. It has three tracks and the music has been converted to MIDI as the licenses ran out. It's emulated via ZSNES.

All the more reason for a proper rerelease, wouldn't you say? Shame about that. Oh well. But one could use the MSU-1 support some SNES emulators have to give users the opportunity to put the original tracks back in... No idea how much effort that'd be though.