I did post couples of years ago about news of Songkha. It is a provincial capital that unfortunately did not get any benefit from economic boom during 1980 - 2000, because all of investment fund went to nearby commercial and transportation hub city of Had Yai. With lack of rapid development, it was one of few strange provincial capitals that still retained old historic area quite intact with old city wall, old city gate, shophouses etc.
The WHS idea actually inspired by Malaysia's Georgetown and Melaka. Local university and NGOs campaigned to preserved historic area and set the goal to become WHS, they claimed that if Penang can be WHS, why not our town! and it will attract more tourists.
I visited Songkha last year for my friend wedding, so this is my opinion, the historic core is a bit too small with only 3 streets, there is no significant buildings to show something that really unique. There are some nice colonial, Sino-Portuguese and even Art Nouveau buildings, fine Chinese temples, Thai temple. But to compared it with Georgetown or Melaka is a bit ridiculous. Its scale is comparable to Phuket old town or Hoi An. But I heard that there are two nomination zone, one in the town and the other on the hill opposite the lake shore. I have no idea on the latter part which heard to be full with old government colonial buildings and fishermen villages.
A chance of flying? Hard to say, remember what we discussed in Bangkok? It is very unique that Thailand, the country that escaped the colonization, has too many colonial buildings similar to Malaysia, Indonesia and Vietnam. While in those countries their architecture dominated by the trend of their colonizer. Thailand's western architecture developed by their own taste, there are French, British, Dutch, Italian or even German styled colonial buildings in Bangkok and many provincial capitals. Songkha has that Georgetown and Melaka have but in much smaller scale, but its story behind is different. So I think it is depend on how to write the nomination dossier. But to be honest it is a poor choice, I would prefer old Bangkok, Chiang Mai and Nan than Songkha. Also I believe this nomination is a bit too rush, well this maybe a result of regional rivalry. There are WHSs in almost every regions of Thailand except the southern. So there are many plans to nominate many sites from Southern area e.g. Wat Mahathat of Nakhon Si Thammarat, Songkha Town, Ranong Mangrove Forest, Andaman Sea. While the recent movement from the central government seem to focus on Chiang Mai in the North, Phanom Roong in Northeast, Si Thep and Death Railway in Central region, nothing from the south. Songkha and Wat Mahathat are purely supported by provincial government and NGOs level. With lack of real support, I have no confident in nomination document! but even with full support from the government, the outcome on OUV presentation maybe still bad similar to Phuphrabat case.