As originally conceived C-Bill transfers were meant to allow players to "get to the next tier" of 'Mechs that they would not otherwise have been able to or to beg/borrow enough to fulfill a repair or rearm requirements. Instead what we have continually seen is "start of game, 2-3 players dump all of their C-Bills on one player, that player buys the largest, heaviest Assault 'Mech available - proceeds to stomp the living crap out of the other team" and this was particularly prevalent with organised units "Clans" that already had the benefit of Teamspeak coordination and the experience of regularly playing with one another.
If you still want to have larger C-Bill transfers, League Mode allows for that. We hope to have the proper C-Bill banking system done sooner rather than later, but we were tired of seeing the bankroll effect against pub teams, it was really disheartening to new players.