This entirely depends on what you see as the problems of the NUB; whether it's that the NUB has led to many of us Vets being unable to reach the top; or whether the NUB disadvanatages vets by requiring 4 months of solid gaming compared to however many months it has taken for the top players to get to the top.
In my eyes; my problem is that the NUB is a huge advantage to any new player who is able to advance their character far beyond what someone who has fought exactly the same amount of fights and put in as much effort.
To correct this; I believe rather than increasing the NUB; and creating the NCB; the most fair option is for new users to be able to buy the extra BA so that those at the top who have put in the effort are not discouraged; and so that those who have not had the chance to spend the 300k fights that ranger has can spend the time and fairly challenge for the top. By doing this; Ranger has no right to complain if someone passes him; they've put in as much effort; however a new player still has the opportunity to get to the top; as they've put in as much effort as Ranger. Maybe the NUB in this form could be extended to the length of time CB has been going; ie that if the top player has fought 300k battles over 300 days; it would allow people under this NUB to purchase an extra 1000 BA per day compared to people not on NUB
While the NUB continues as a rewards bonus; I believe that the game will continue to lose previously active members and respected veterans. Even with the NCB; i do not believe it will be enough. partially I would put this down to the difficulties in getting rare equipment for developing characters without keeping the old characters respectable and playable