Account sharing may be a "small" issue, but it does not solve the issue of 20k+ accounts that are basically in no guild but get more than the average and even more than the highly active players.
I have a feeling that there are 1000's of simulated users run by the Dev's and we the players are competing with these false players. Even when I played 40+ hours a week on this game and was getting many trophies, 1000's of games in pvp, I could still never compete with the top.
Something just seems a little fishy with it.
Also with the IP restrictions and supposed account sharing, there are people whom must use a VPN for work/business and also might use mobile with different ip's even from different regions. Or people who work in different locations, play at home on others and maybe login to from a starbucks or mcdonalds wifi somewhere else even on a daily basis.
If there truly were 20000 active players, why wouldn't they be in the top guilds, and if they are earning trophies at rates faster than the current top guilds why do they never rise? Many questions that are probably unanswerable.