So I did a homegrown (absolutely 0 players from TL) back in the S20s. And there was a definite ceiling of D.II middle of the pack was as high as the team could achieve. Now, it might be *possible* to go farther now, with the decline of skills of players pushed back farther, and advancements to arena facilities since then (training court for FTs, gym for helping with those multi-position trainings one has to do as 100% home grown). But I do agree that there is a limitation to the possible success one can attain doing such a strategy.
It is very hard indeed, yet some of the teams have managed to do very well with being homegrown. For most managers it's not probably realistic to expect a massive success when becoming homegrown, but on the other hand it offers so much more when you do achieve some success. Success, however, isn't comparable to other teams in your league (you are very lucky if there is another HG team in your league, as there are not so many of us), and that's where this new Homegrown League would come handy - we all would compete within the same rules and restrictions (and not against teams that have been built by purchasing).
Those changes you mentioned certainly help - even though benefits of them are available to all but still they are so essential to HG teams.
I don’t know if they had planned to have a separate league just for teams that do this, and if they did, I cannot imagine how they would try and implement it since it’s so easy to break out of homegrown. But, if this was a thought they had- how would they fairly provide the equality to teams of this nature to where they could fairly compete for BBB as a homegrown team?
I'm not aware that anyone would've planned anything in terms of creating a separate (practically additional league, bit like a PL but without the need of being a supporter) league, and that's why I took an initiative on this. I Still haven't approached Buzzerbeater staff/owners about this though, but maybe if they read this and want to discuss things further they can of course participate the conversation here or send me a message.
If one or some teams participating would become non-homegrown during the season, I guess one of the ways to implement it would be so that your team would be thrown out of the league immediately if they lack homegrown status at any part during the season (and possibly bot would replace that "forfeited" team in the league?).
As for the comment about HG teams being able to compete fairly in BBB, I'm not sure I understood your point (sorry, I'm not a native speaker...). But if I understood right I guess that it would be way too much to ask from BB staff to consider that, and personally I wouldn't expect them to make any changes in homegrown teams' "ability to compete in a fair manner against other teams" - that's one of the reason's why I'd like to see BBHG league in action, because it would be "an isolated league" from all the other official leagues, and then there would be finally a possibility to determine the best homegrown teams in Buzzerbeater.