“Does the philatelic value of a stamp depend upon the size of a country? If so, would stamps of say, Bhutan have any value in the philatelic environment?”

Size of a country I am sure, is of no consequence. Take for example, issues from Tonga, New Zealand, Bhutan as you have suggested and many other smaller countries, they are mostly very beautiful. They are also topical, and hence, I am sure these stamps must be very popular with collectors around the world. At least they are with me. Not being in the philatelic trading business I won’t be able to answer the second part of your question. For a satisfactory answer to this part of your question, you would have to consult professionals in the trade. But, I do believe that the most valuable stamps in the world were issued in very small countries.

On the other hand if by ‘value’ you mean importance, then I can confidently say that Bhutanese stamps must be occupying an important niche in most collections around the world.

Lets now take a look at some of my favorite Bhutanese stamps to see and understand what I really mean. The famous ‘Tankha’ stamps were printed on fabric. Coin shaped stamps are a rarity in most countries The Gold coin stamps were issued to commemorate the 20^th Birthday of the former King Jigme Singye Wangchuk. Bhutan has also issued stamps in every format. 3D and embossed lovelies were issued many years ago. But, I now believe that have also introduced stamps in the CD format.