Since the changes are only temporary they would not really need to adapt. They have big enough arenas to keep up as strong a cash flow as the rest of us, and when the taxes are ove they would continue to reap the benefits of their large arenas. The changes as they now exist mostly punish the teams that are the biggest victims of inflation.
For example: The Torooo tax hurts every single other div I team in Canada more than it hurts Torooo because he has the biggest arena. An arena tax would level the playing field for the two or three seasons it is in place, rather than widen the gap between him and the rest of us.
I do not think it is a major flaw at all. If it was a change for just half a season or something like that I would agree with you, but even if temporary, this is something hat will be here for at least a couple of seasons.
Of course an arena tax would level the playing field (as an example I would gain on the big team in Sweden HHH), however it would be an unfair way. The reason why teams like Torooo and HHH are in a better position then me is because they have started before me and that they have managed theor teams in a good way. I cannot see why they should be punnished for this.
If you have played your cards right there is no reason why you should loose out compared to Torooo as a consequence of this change. If we, until now, have managed our teams optimaly there is no reason at all why we could not do this in the future. It is in fact just a matter of adapting.
With that said, I think it is unfortunate that BB designed the game in a way that made it possible for a few teams to "run away", but I cannot see why they should be punnished for doing this.