we can vote ,but since the voters is so few, less than 50,compared to over 2 thousand stakeholders,so the final decision should be made by all developers, because the total supply number is key parameter for a new coin ,and developers must balance the pros and cons seriously.
Anyway,if stay unchanged( 3.99billion or 4 billion), I like to hold for long time ,if doubled, I like to sell half in short time.