Do you think that emiratization in private sector is a threat for expatriates in future?

In my opinion no. The fact that emiratis are employed to the private sector is a good improvement. The economy and labour market should primarily belong to locals like in any other country. I guess UAE is the only country in the world that allowes the huge overflow of labour from other countries. That has already caused problems e.g. trafficing. As we speak, many countries are working on to further tighten the recidence laws because foreign companies are laying off locals and employing own people, e.g. TCS in US, Australia and in many European countries.