All I can say is UAE Government is pushing hard to promote tourism and business in the country as well as leading the innovation race in the Middle East (all these outside the Oil Industry). And they themselves invest heavily on infrastructures. They want to be number 1 in the world! Though the property price as the world knows fell significantly during the recession in 2007/08 and up again dramatically by more than 20% in 2013 (Land Department statistics)
Factors to consider:
Pros: Apart from Expo 2020, more investors are still making Dubai a place of choice for investment. UAE wants to be number 1 in the world and they are doing something on it far beyond 2020!
Cons: The law of supply and demand doesn't make sense in Dubai. Some areas remain low and some areas are significantly too high.
With regards to the worldwide investors objective... it will depend if they are looking for capital appreciation or good rental yield. It's like investing in London on 3% rental yield but with high capital growth and/or place like Manchester and Liverpool where the rental yield can reach above 8% but with low capital growth. In Dubai, certain areas like Business Bay, Downtown, Marina, JBR and Palm are stable for flipping while in Deira, the rental demand is too strong!
Property investment is a matter of having a good strategy and intel within the area particularly for the BMV hunters like me who hunts properties for my friends who always want a good return on their investment. It's all about Location... Location... Location...
Hope this helps.