If there is an ash cloud, there is one and you have two choices:
-stay at home
-make your way to an alternative airport and hope for the best.
I went for the second option about a month ago and made my way from London to Nice via train to get out of Europe, on the way home I could go back to London but it could also have been that I would have ended up stuck in DXB. You never know. Emirates can't change much about that either. This is nature.
Regarding Thailand, on one hand it is not as bad as it is made to look on the media, especially not if you are just going for a holiday and nowhere close to the affected areas in Bangkok. On the other hand one could say it is your decision. Go or stay at home.
In the end you just have to make a decision based on what you think is best, so wait patiently until closer to the date. Although flight cancellations due to the ash are not covered by travel insurance you might still get your money back based on the fact that you are going to Thailand. Make sure you check with your insurance whether they would refund in case you cancel your trip.