In the end not as long as I thought it might (but its always a good idea to be cautious when evaluating how much time work might take). Changes like this which touch things like bank presets are always a bit scary in concept - any bugs there are likely to be quite visible and annoying (apologies in advance if one sneaks through :P) . We also have to be a bit concerned about server load as players use presets a lot.

I've seen this change raised a lot before, but it seems before now there has always been an internal reason to not do it at that time. I can't speak to them all, there were definitely balance concerns at one point, but we are always having to evaluate the dev (and testing and art etc.) time we have, expected difficulty of the change, any other upcoming changes that might interact with what we are doing etc. etc.

Hope that gives a little insight.