The linear upgrade system is pretty dull and really does not give players many options.
Back in the day WOTC had the option for players to suggest upgrade packages to be added if they were not included( don't have link to the thread)
I feel such an option here would be a better compromise than the current system. It could be set up the same way when you want to start on bb or dd line by having the option above the linear line.
Would this be feasible or acceptable ?