Exactly.
I can’t stress how great it is to better understand the structure of the training plans (e. g. whether a workout is marked as Achievable, i. e. it is meant to be easy, or Progressive, that is, a harder workout aimed at making gains). And progression levels are very useful at gauging how hard a workout will likely be.
Like you said, it errs very much on the conservative side, because (according to TR’s support team) they are using a single progression level decay model for all athletes — and they are erring on the conservative side. Nevertheless, despite its shortcomings I definitely wouldn’t want to miss it.
To be honest, rather than fiddling with the underlying algorithms even more, after public release, I hope the TR team will turn their attention to how it presents the, well, progression of the progression levels over time to the athlete. Something like TrainingPeaks’s graphs to gauge your fitness in specific areas would be great. It’d be really nice to see your progress at a glance, as compared with, e. g. the same point in time during last season’s training plan. I understand that this is tricker than at first glance, because progression levels change as your FTP changes. So you have to make sure that you don’t associate a drop in progression levels after an FTP increase with a loss of fitness.