See it looks like casters have the same amount of proficiency with skills to use and wing it with as well as their I can do this now passes. What If they had to put skills into spell schools or similar I have to train in these 2 magical skills which are really just access passes for the learning spells and not of much value outside of that.
BA even has people deciding its wrong to let rogues have expertise because it looks out of sync or some such. I am thinking to challenge one of them you have to have obstacles completely out of reach of everyone else might be the complaint or something. But what better performances might I shoot for ... shrug. wave your hands in the air. How much are we cramming in session zero?
Six skills: rogue
Five skills: bard, ranger
Four skills: barbarian, cleric, druid, fighter, monk, paladin, sorcerer, wizard
That's where it sits at a first glance but the number of proficiencies is misleading. One of the key differences that becomes very prominent in play is the focus on ability score bonuses the way it's set up drastically influences skill bonuses. A fighter with a +5 STR bonus get that bonus to much different checks than a wizard with +5 INT bonus. This is true whether they have the same number of proficiencies or even if they take the exact same proficiencies. BA DC's are basically a measurement of 1/3 proficiency, 1/3 (natural) ability, and 1/3 average likelihood (chance and/or circumstance).
Only looking at the proficiencies and proficiency bonuses is ignoring the greater bulk of the equation.
Expertise is actually included in the BA math for those rare 25 DC's and chance (getting lucky) applies to the possible 30 DC's. It's not that expertise is out of sync with BA. It's that people see a bonus and think their favorite class should also have the same bonus even though DC 20 is the normal high / hard task that requires full proficiency and ability score to be reliable under pressure and represents extreme ability.
BA DC's are based on the bonuses possible, not the other way around or in spite of them. It's a number porn concern. Which if funny because those DC's only have meaning if the character is trying to do something that spectacular in the first place and defined as in doubt by the DM. Without that context it's bigger numbers for the sake of bigger numbers. The fact that characters can reasonably try such an action even with a 2-5 point gap in the bonus is the benefit for BA.
I'm going to also use an example of the paladin in our test campaign right now. The group often tries to ambush if they can. The paladin sucks at stealth -- 10 DEX, no proficiency, armor disadvantage. The ranger and bard both have proficiency and 16 DEX / 14 DEX respectively. Neither the sorcerer nor the wizard has proficiency but both also have 14 DEX. Sneaking in as a group and using a group stealth check makes the paladin's terrible stealth almost meaningless. Against typical passive perceptions it's generally a lost cause for the paladin, generally a success for the ranger or bard or both, and statistically likely at least one of the other casters makes those checks. A group check means they need 3 out of 5 characters to beat passive perception so the odds are in their favor.
Now it's not just one or two scouts moving ahead. Never separate the party.
After the basic class plus background proficiency bonuses plus ability score bonuses (which covers more variety of checks than the actual proficiencies) we're looking at add-on proficiencies from races or subclass, or actual class enhancements. The half-elf number of bonus proficiencies is worth just as much as a class or background, and that would move a sorcerer up to 6 proficiencies before a barbarian, but would also move a paladin up before a wizard. Jack-of-all-trades covers a lot of bases while reliable talent is fantastic.
I don't want to derail again, but I would also point out fighter subclasses tend to include benefits with some more often than others. The UA rune knight gives a lot of skill benefits, for example, but the minor benefits seem to happen more often with a fighter subclass than with other subclasses.
I just wanted to point out that ability and skill checks vary by a lot more than the number of proficiencies. Equal number of proficiencies doesn't actually create equality in those choices because of the other related factors.