Love alot about the playtest. Same concerns as many people here, hoping a bunch was cut out to make it playtestable, bones are good, and not feeling adding Level + Proficiency to everything.
It's almost certainly not going to change. It's the kind of deep assumption in the mechanics of the game that doesn't lend itself to change: they built the whole game and possibly their business model on this.
That being said, it is on basically every roll, therefore adjusting it might not break things horribly. So, a potential house rule: instead of a flat adjustment, make the Proficiency modifier a fraction of your level:
Untrained: +(Level x 1/8) (round up!)
Trained: +(Level x 1/4)
Expert: +(Level x 1/2)
Master: +(Level x 3/4)
Legendary: +(Level x 1)
Or something like that. This way you get +1 in a Trained roll every fourth level, +1 in an Expert roll every other level, +1 in a Master roll every level except for every fourth, and +1 in a Legendary roll every level. At 20th level Untrained rolls are only +2 better than at first.
Basically, you'd get better at everything, but the rate at which you get better in things you didn't invest in is slower.
You'll run into trouble with the Bestiary, it will be very difficult to on the fly modify monsters for this system. Otherwise you'd be treating every monster as your Legendary, whcih is the default Trained, and theyn some would have bonuses on top of that. It would pretty much break to hit and AC.
What I have suggested in another thread is just stripping out the "add your level to everything". It will orked, I call it Bounded Pathfinder. Its actually less bound than 5e is. This way all you do is subtract the monsters level from all the checks its level was added to. Not terribly hard to do and will address your concerns.
I doubt it will change, but ironically, it woudlnt' be hard to remove. I doubt they will, but it is easy enough to do on your end. I have a feeling it'll be the most common single houserule, especially for those like myself that abhor level scaling and like bounded accuracy.
There have been tons of post like this, each suggesting new magical numbers to make the system 'work' again.
I don't think that suggesting numbers is useful, but it's undeniable that a lot of people doesn't like character level add to everything. Personally I'm ok with that, even if it doesn't really make sense in some particular cases.