I'm happy to pay again but not this much (as small as it is) ...$12 with a measly 9% discount for a 23 year old game.

Come the f**k on guys.

AU$ or US$ ?

It's $10USD to me, so it must be $12AU. Either way he's correct, it's overpriced but I guess if the rose colored glasses crowd will pay that it'll be there until they've worked their way through that groups and sales stop.

Frankly I'm surprised at the reviews, as I remembered never caring much for Diablo, and seeing the reviews mentioning slow and clunky, yep now I remember why I couldn't stand it... (at that time I'd've probably been playing Daggerfall anyways or Wizardry 7 along with some real roguelikes e.g. ADOM(first came out as 'postcardware' around then IIRC), Angband(or one of the other host of moria(and angband) spawn)...

By the time I played it which would've likely been '97 I probably had a 233MHz pentium, so it was the game itself that was slow and clunky... and it was probably the clunky part that really turned me off, so for me, $10, is not worth buying and trying again, or even $9. Maybe If I stumble across the CDs again I'll try(and prolly bounce) again...

I payed $10 USD the exact same moment i logged into GOG Galaxy and saw Diablo1 finally on sale. Don't regret one bit and i already got over 1500 hours playing Diablo/Hellfire on GOG Galaxy. WarCraft1+2 was a different story... i still bought it, but i sort of feel it was over priced. I guess it depends how much you love certain games. For me D1 was instant buy and i would even had payed an extra 5-7 USD for Hellfire, but at the end it was free!

It requires replacing one dll (or using devilutionX). I'm using one of my original CDs (I've got two – don't know why).

Which dll is replaced, and with what?

ddraw.dll

There are several possibilities. Devilution's (not devilutionX) readme recommends this one: http://www.strangebytes.com/index.php/projects/1-diablo-1-windows-7-vista-patch

THIS

The price is fine but the discounts are super meagre. Today it's an amazing 15% off, 5% more than I've ever seen it before. GIve it a year and maybe we can get 30%

I think the price and lack of substantial discounts is on Blizzard/Activision, not GOG

OP believes you shouldn't have to wait more, for a nice discount, as there was a gap of (nearly) 23 years, since the game was released. I agree. If you're going to offer a discount, it's about time to do something actually nice.

At least, there's no risk of you losing installation disc(s), the game will stay forever in your Gog account (even if Blizzard decides to remove the game, from the store).
Also, if you want to see Diablo II / LoD here, it seems to be a good move. Blizzard won't consider bringing the classic here, if there's barely any interest in the first game, I think.