Here's my attempt.
Instead of defaulting on its loans and attacking the Ottomans 1897, the Greeks stay put, lower military expenditure and pay off some of their loans. The Greeks never defaulting on their loans in modern times should make their credit value better, and thus interests lower.
The Greeks still get Crete by international settlement.
Venizelos defies the King and refuses to resign in 1915, instead all of Greece joins the Entente 1915 - the Ottomans and Bulgarians fall a few months earlier 1918, and Greece is rewarded with Cyprus (but with British basing rights), northern Epirus (southern Albania) with substantial interests in the rest of Albania, Bulgarian Thrace (as IOTL), Turkish Thrace (as IOTL), the straits (but demilitarised) and Ionia (as IOTL). Population transfer (in reality, ethnic cleansing) happens on both sides and a lot of Greeks, Pontic Greeks and Armenians as well as other christians in the former Ottoman Empire now controlled by the Turkish Republic ands up in Greece.
Also, Wrangel's fleet with the refugee White Russians from Ukraine and Crimea stays in Greek constantinople. Greece is, due to religious similarity, proximity to Russia and land for sale from the state (seized from Turks) the favoured place to settle for White Russians fleeing the revolution.
Greece is a staunch ally of Britain and France, especially as Alexander (who has ruled since 1915, when King Constantine abdicated in the conflict with Venizelos) does not die from being bitten by a monkey and recieves military and economic aid. Venizelos reforms the election laws and continue to rule, weeding out corruption and setting up a small welfare state along Bismarckian lines.
The British transfer the two battleships Reshadieh/HMS Erin and Sultan Osman I/HMS Agincourt and the White Russian fleet transfer most of its vessels, including the battleship Alexander III/Volya/General Alexeiev.
The Turks refuse the treaty, but the Greeks also only occupy the terrain they have taken. After a few years an uneasy truce develops, while France and Italy abandon their influence zones soon - the Greeks offer to take over those zones, but only takes small parts of the Italian zone north and south of their Ioannia enclave, and leaves the rest to the Turks, adding to the Turkish reluctance to attack.
British, White Russian and French investment in the Greek economy during the inter-war era, the rather rural status of the Greek economy and careful husbanding of resources lets Venizelos see Greece through the depression comparatibly well.
When ww2 rolls around, the Greeks declare neutrality. At the same time, they work hard to improve relations with the Turks, giving back a little territory and doing more (this time peaceful) population transfers. While parts of Greek society wants to join the allies, especially after the Italian takeover of Albania and entrance into war, cooler voices prevail. Especially the White Russian comminuty is anti-communist and many volunteer for the SS, while Britain retains basing rights on Crete and Cyprus, but not rights to over-fly mainland Greece.
Mussoline does not attack Greece, as Greece looks strong on paper with 3 battleships, 2 light cruisers, 1 armoured cruiser, a small airforce and a large army which they can concentrate in the west against Albania. The Germans also wants to avoid fighting in the Balkans, and Hitler informs Mussolini of German troops entering Romania. Churchill wants to get Greece into the fighting, but the Greeks push back and Greece rather successfully plays both sides, trading with both and purchasing arms. With the demilitarised straits, the British can send ship-borne aid to the Soviets (which are attacked a bit earlier, due to no Balkan front) through the Black Sea, although German and Romanian light vessels contest this trade, and the railroad through Persia quickly becomes more important as a life-line.
WW2 ends pretty much on schedule, with Greece and Yugoslavia untouched (a attempted coup and following guerilla warfare by Croatian nationalists having been crushed by the Yugoslav army). Greece takes in a lot of Polish refugees (both AK and Polish Army in the West) and anti-communist Bulgarians and Romanians (who often are their country's respective elite, that bring as much resources they can with them). Greece continues to be a fairly stable democracy, with a decent economy and a tradition of decent budget handling since 1920 or so.
With marshal aid, entering NATO and lessening military expenditure, no Junta and revolution, no civil war, no occupation, no war for Cyprus and less to prove against the Turks, the Greek economy does much better. Greece as a tourist attraction develops earlier due to the better infrastructure, economy, safety and democracy and while Greek food cannot completely rival Italian as delicacies all over the world, it is still a strong contender.
Greek industry excel in shipbuilding and shipping, with Greek engineers sought after when it comes to construction of infrastructure in mountainous terrain and innovative road-to-ship and railroad-to-ship roll on-roll off solutions. Greek cheese and bread as well as cured lamb's meat are considered delicacies. Greek arms, especially in the areas of speedboats, torpedo and landing crafts and littoral warfare are highly regarded, with the US Marines as one user (through licensing to an American company, of course). Food processon, fishing, porcelain industry, wool and textiles are also notable Greek industries.
in 2012, the Greek industry suffers from competition from southeast Asia and the recent downturn has hit the economy hard - but the Greeks have a solid and decently funded education system and is making good inroads towards turning from an industrial economy to a post-industrial, service based economy, with the IT sector going well.