Well, Greece would be in the same situation as Denmark, in that their currency would be pegged to the Euro as part of ERM II.
(This is what certain economists miss in this-the European countries didn't go free floating->Euro, but from fixed currencies bound in ERM).
This would mean that they wouldn't be able to devalue significantly unless they remove the peg...
I don't see that happening unless it's after a very hard fight against speculation...
I mean, even right now, Denmark is still defending their peg, and they got the backing of the ECB's reserves to do so, meaning that it's unlikely that the unpegging would happen...
So maybe Greece would still be defending their peg like Denmark is now, or we get a Greek equivalent to Black Wednesday where Greece crashes out of the ERM like the UK did, which would still be better than OTL as they could devalue their currency...(though devaluation may not be a panacea if significant transactions aren't done in one's own currency, like in Croatia).
The other "PIIGS" countries would have the same issues, but it may be less contentious because there was quite a bit of pre-existing ill-will towards Greece before the crisis occurred, what with the whole Macedonian name issue, their willingness to veto the 2004 expansion in exchange for letting Cyprus in, and the sense of "buyer's remorse" of letting Greece in "too early" (as their entrance was approved by the Council against the Commission's recommendation).
Though I still think there would be contentions...and ironically maybe Greece would complain of having to bail out say, Portugal!