Quickleaf
Legend
Do you feel any concern that some class features (the ones I cited) are rendered fairly valueless by this approach? Do those features seem more or less like design errors?
Not really, no.
There's a difference between lore that hints at potential stat info (skill check) and telling a player a monster's vulnerabilities outright (Hunter's Sense). Look back at my example – yes, the player who made the Religion check guessed that the wight was vulnerable to sunlight, but they had no idea about silver overcoming a wight's resistances. In fact, the party had a silver weapon, but no one thought to use it, and the fight was harder because of that. If a Monster Slayer ranger had been in the group and spent an action to expend a use of Hunter's Sense, they would have had that information.
Similarly, the Monster Slayer ranger's Hunter's Sense wouldn't have picked up on all that juicy lore information about wights, particularly they would have missed out on "You've heard stories of ancient human civilizations in the jungle whose aristocrats and priests voluntarily become undead, their wicked hearts and minds sworn in service to the dark entity that granted them undeath" (clue about being failed warlocks which hints at spellcasting capabilities, and clue about voluntarily embracing undeath which is relevant to the rest of the adventure) & the bit about "It is said that the moon was so offended by the sight of these wights crawling from their ruined cities at night that she cursed them to reveal their true forms under her light" (a clue I made up which makes the sun dispel any disguise self a deathlock is using). The Monster Slayer would have missed out on all that.
So, it depends on your point of view. Are there parts of D&D that are important which have nothing to do with combat or even dice-rolling?
If you're the type of player who would answer "no, the important parts are where I kick ass", then you probably don't see any use in the Religion check, while favoring Hunter's Sense.
Conversely, if you're the type of player who would answer "absolutely, yes", then you probably would prefer the information offered by the Religion check, and would view the Hunter's Sense info as inferior because it's only of short-term use and doesn't shine a light on the bigger picture.