1. None. Would only buy games with no regional price hikes (not just here, but in any region) and just have a few of those left on wishlist and none I'm particularly interested in. At most, may end up getting a little something for the community giveaway, or (highly unlikely, but happened once, so...) maaaaaybe something for a trade, but again, only as long as whatever I'll purchase won't have regional price hikes, and also as long as the codes for the game(s) I'll trade for will already be purchased, so I won't cause a game with regional price hikes to be bought either.
2. Out of those I already played, or am playing? Somewhat newer stuff, Lords of Xulima can be interesting for the right kind of player, but guide is VERY useful, and the talisman is handy too, so that's one where the Deluxe Edition really is very preferable.
Tropico 3 (with the expansion) and
Tropico 4 (with DLCs but not necessarily including Modern Times) are all right too.
Wouldn't call Ember bad either, though it has plenty of flaws (and skills determined solely by gear? seriously?). Older ones not in the top 100 all time sales? Hmm... Risen isn't bad either, neither is the first Two Worlds, maybe
Age of Wonders 2, Anachronox if played with a guide to not need to do the pixel hunting, maybe Septerra Core, maybe The Bard's Tale (2004) for something more humorous, maybe Evil Islands mainly for the crafting system, I'd clearly say Homeworld 2 but really don't want to support overpriced remasters... Probably don't need to mention Betrayal at Krondor or King's Bounty: The Legend (though, judging by sales position, maybe I do).
3. The concept of insomnia remains interesting, but doubt they'll do it again now that they're just another mainstream store. Could do with rotating flash deals if they do it smartly, I'd say either 5 batches of 6-hour deals repeated 4 times (total: 5 days - fitting for a one-week sale with the last 2 days being the "finale") or 4 batches of 8-hour deals 3 times (total: 4 days, fitting for a two-week sale, with 3 rounds like this and a 2-day "finale"), so each batch will appear in each hourly slot eventually. Also badges or XP that may also add to greater rewards for purchases but should add up to the first tier free game with no purchase (or installation of Galaxy! or social media interaction, or other such things) necessary, so for logging in daily or other basic stuff done strictly on the GOG site. A scavenger hunt may be interesting too.
And I'd really want a return to the contests they used to make on forums (questions on forums, answers by e-mail, ofc), like those with riddles, questions, finding game names in the block of letters, stuff like that, properly announced in advance so people will know when to be ready and with first X getting a guaranteed prize and draws for some more picked from the others who sent all correct answers within 12h or something like that. But that's another thing I doubt they'll do again...
PS: 3a. What I do NOT want to see, on the other hand, are gambling purchases, mystery games/bundles. And also no rewards tied to using Galaxy or using social media, or anything 3rd party for that matter.