Parmandur
Book-Friend, he/him
The trick is that the formula there is almost exactly what it was in 3e, except that they've given names to all of the different kinds of bonuses and penalties.
From a game designer perspective it makes sense - you want to be as precise as possible when you're designing the game. From a game learner perspective it looks kind of ridiculous when it's spelled out like that. If the formula were written as:
number on the die + ability modifier + proficiency modifier + circumstance/conditional/item bonuses - circumstance/conditional/item penalties
it would be less weird. If it were:
number on the die + ability modifier + proficiency modifier + bonuses - penalties
It would be basically describing D&D since 3e. Though 5e worked to get rid of a lot of bonuses/penalties by introducing the advantage/disadvantage mechanic - though arguments can be made that that mechanic doesn't have enough granularity compared to bonuses and penalties.
(I do think that there's an argument to be made that the playtest rules feel like they are too "game designer" focused rather than for a more 'general audience'. I don't know if that's because it's a playtest document or if they're making the same "mistake" that Wizards did with 4th edition in that respect, but I can see it.)
The 5E formula is number rolled + Ability mod + Proficiency mod. Bonuses and minuses might apply, but those are exceptions rather than rules. So, outside of corner cases or special abilities, all that is needed is the die roll and two static numbers prominently displayed on the character sheet.
Now, a game doesn't have to be quite so streamlined and elegant, but...it is attractive.