By now it’s possible to delete your account (source: https://support.worldoftanks.com/Knowledgebase/Article/View/108/22/how-do-i-delete-my-account ). From that page:
Please send us the following information through the ticket system (to be found here https://support.worldoftanks.com/Tickets/Submit ):
– A screen shot of an online bank or billing statement (On-line bank transaction screenshots only – We do not consider screenshots of email inbox notification), demonstrating any World of Tanks payments.
– We also need the following information regarding your account registration:
When did you register your account?
What city did you register your account in?
What ISP (Internet Service Provider) did you use to log in and register your account?
– A brief explanation as to why you would like your account to be permanently closed.