This is looks quite nice.
Already cracked 2 accounts.
I'm new to minecraft cracking, but I think the best way to get usernames is scraping them from servers, isn't it? And for password lists, is it the best to use small ones (because that's faster) or would it be better to use larger ones (although that'd take more times)? Would getting a server a good idea to run this? Also, does OVH allow it or could they suspend the server if they find out?
Some suggestions:
* Safe all working proxies (remove the not-working ones) in a text file
* Same suggestion as above, but with the usernames. Migrated and non-premium ones should be removed.
* Make the same as a command line tool, so you could run it on servers without any desktop environment.