Here are the obstacles to improvements that might make more new managers stay, and this is where my comments tend to get very unpopular.
BB has always been a 'top-down' game. Those veteran successful managers are established in the community, they have friends and clout and ....well.... easier access to the ear of those who make changes. In essence, their opinions matter, new players opinions don't (this is not worth debating, really. Lets assume the usual 'we listen to everyone equally' is heard, responded to, and moved on from). Those who have worked hard, been diligent, made friends, and are successful now are very happy with the extremely steep slope of advancement in this game, and they are very unwilling to accept changes to the game that might flatten the slope (to their disadvantage). I get that, I would be the same way. The problem is that the steep slope is what causes the futility-quit epidemic that has the game down to 1/3rd of it's users since I first quit the game way back when. There are guys who have dominated my D4 and have pretty solid teams by D4 standards who go to D3 and go 2-20 and quit. A big part of this is their lack of understanding of what it really takes to move up successfully, but the steep slope is also to blame. The point I am making is about keeping new managers interested and growing the game and not 'make things easier for me specifically'.
I say all of this because one of the problems with suggestions/changes to the game is that if any suggestion would help flatten the slope or make newer managers more relevant and interested, they often would work against the top tier veterans from remaining entrenched, and the outcry from managers who are more established (see above) tend to have more weight with those in power to make changes than a bunch of newbie managers no one has ever heard of. This is why it is a bad idea for those who make decisions to become 'friends' with the long time managers, or to have their own teams themselves ()not talking forum mods, talking actual people who make decisions about the direction of the game). There usually is a firewall between these people and the gaming community, which this game has never really had, and directions that can grow the community get influenced by the connections between veteran 'friends' and those in power.
Sure, we can turn this into a debate about whether this actually happens, but that isn't as productive as addressing the problems with keeping new managers interested, it's tangential.
When addressing the problem with an ever shrinking user base, it is much easier to create impactful solutions from the bottom-up than the top-down. It is much easier to replace the top 16 managers than it is to replace the bottom 256 (I say this wearing head to toe Kevlar and hiding behind a concrete barrier screaming in my best Swarzeneggar "GET DOWN!")