I sugggest making a transparent Xp system. Like some just suggersted.. 1:3 1:4 ETC ETC. Your XP shouldnt be a guessing game.
Im all for learning to play the game and play it correctly...but the amount of games needed to level a new higher level bb is a bit on boring side. I read on another post someone haveing to play around 6000k battles...not sure if thats true or not but it sounds about right
as for transparency everything about this game is too dang complicated...
As it stands now. here is the current XP formula
2xY+10-5/2.14 if x=1.3 than EXP = y+3x30-3.1459xλ.....................