But they are more expensive somewhere, right? Like Western Eurozone, UK, maybe Australia?

Are they? I don't know. Since Greece is considered part of the Western Eurozone, they certainly aren't for me. Which is why I said above "but I can't confirm if that's the case with other territories."

I'm getting annoying with this, but the answer I'm looking for is; are the aforementioned games, which are not more expensive at Greece, more expensive somewhere else?

Yes. Hatoful Boyfriend is more expensive in Great Britain, for example.

hatoful_boyfriend
US_USD -> GAME PRICE : $9.99
GB_GBP -> GAME PRICE : £6.99
GB_USD -> GAME PRICE : $11.19
FR_EUR -> GAME PRICE : €7.99
FR_USD -> GAME PRICE : $9.99
DE_EUR -> GAME PRICE : €7.99
DE_USD -> GAME PRICE : $9.99
PL_EUR -> GAME PRICE : €7.99
PL_USD -> GAME PRICE : $9.99
AU_AUD -> GAME PRICE : A$11.49
AU_USD -> GAME PRICE : $9.99
RU_RUB -> GAME PRICE : ₽249
RU_USD -> GAME PRICE : $6.09
MX_USD -> GAME PRICE : $8.99

That's strange. All of them were more expensive in Germany when they first showed up (Hatoful Boyfriend) or after the implementation of local currency (Gone Home, Shadow Warrior). Now the price is the exact same than in the USA. So did they remove regional pricing for these titles or did they just change the price for some (European?) countries?

That's the same exact price I'm getting and it isn't more expensive. For once, I'm not getting a "fair-price package" compensation. You can thank the "Local Prices Update". ;)
I'm not sure about that. Gone Home is a game that I completely missed being regionally-priced when the redesign came, because there was no indication of its price altering. Hatoful Boyfriend initially offered a €0.50 compensation, but after the Local Prices Update, the compensation vanished, as the €7.99 price is pretty darn close to the current $-€ exchange. Shadow Warrior initially had a price of $39.49, which is now $37.79. As for Wasteland 2 Digital Deluxe Edition Upgrade, I found it strange why there was no fair price package being offered, as I thought that it was $15. A bit of searching later, I found out that the price was $20, but locked at €15 for Europeans, which currently translates to a bit less than $19.

That would indeed be nice if there is a trend towards making regional prices more trivial during the periodic adjustments, at least for titles that have been here a while. Could take some of the sting out of the regional pricing policy. I wonder if we should flag these up somehow.

It happened for sure and it goes both ways. Price update was on October 1st and look at what MaGog found on October 2nd.

Sinistar already answered for Hatoful Boyfriend, but here are the prices for the others (USD only):

Gone Home:
AU_USD: $19.99
BR_USD: $19.99
DK_USD: $19.99
GB_USD: $19.69
MX_USD: $19.99
PL_USD: $19.99
RU_USD: $10.39
US_USD: $19.99

Shadow Warrior (2013):
AU_USD: $39.99
BR_USD: $39.99
DK_USD: $37.79
GB_USD: $39.19
MX_USD: $39.99
PL_USD: $37.79
RU_USD: $15.09
US_USD: $39.99

Wasteland 2 Upgrade:
AU_USD: $20.89
BR_USD: $14.99
DK_USD: $18.79
GB_USD: $24.09
MX_USD: $14.99
PL_USD: $18.79
RU_USD: $7.39
US_USD: $19.99

So, the Wasteland upgrade is a little more expensive in UK and Australia; Shadow Warrior and Gone Home is never more expensive than US.

Thanks, Pidgeot.

Thanks. Setting them separately, just in case. Done.

what's the justification for regional pricing indie games without publishers or disc retail?..... getting way too common

My guess is that some indies just want to get an exception as well.
This is the problem with allowing regional pricing in the first place - Can't make a single exception without others complaining about it being unfair.

At the end regional pricing will most likely become common - Sadly.

Tax.