From this article on PC Gamers, which has a bit more info from a Czech news site, it sounds like the two devs have not been subjected to undue delay.
They've been in jail for less than 70 days, and their appeal (I assume maybe a motion to dismiss the charges) has already been rejected. The US federal statutes governing the time limit between arrest, or was it arraignment, and indictment is I think 60 days barring any motions or continuances that lead to extensions, something that could have been used for espionage charges. I don't know the Greek legal code, but the time frame doesn't sound dragged out. Since they've now entered the pre-trial phase, I wish them the best of luck.
That is not to say the devs are more guilty than before, but I want to introduce some balance to my comments. Just as the devs should not be looked at as though they are already guilty of a crime, the Greek judiciary should not be seen as government boogieman out to make the two's lives miserable. Espionage is a serious crime which may even bring implicit diplomatic accusations against a sovereign state. Although I feel for the two devs and certainly don't want to be in their shoes, I actually support a thorough preparation both for the decision to indict and before the trial. I only hope that since they are just game developers, they be remitted to minimum or other appropriate detention centers that don't make their lives more miserable than necessary before the trial.
There is another possibility, one I only want to say on implicit, general terms. Something unsavory, from a legal perspective, sometimes creep into judicial proceedings of international relevance. Espionage figures prominently throughout history. I hope no regular civilian is ever used as a pawn in such power plays between governments. That would be a real tragedy, especially for the civilians involved.
@Unfallen_Satan From the article you linked: In a report by Czech news site Rozhlas, a Greek court dismissed Buchta and Pezlar?s petition to appeal and denied bail, effectively sealing a required trial with a sentence up to 20 years for a guilty verdict.
They obviously think they have enough evidence against them to go to trial so you're right they haven't been convicted, but it doesn't look good for them either.