But in that example, it’s not that he can’t read today, it’s that in this case, he failed to decipher the riddle, and you or the DM role play exactly why that is.

That's thin meat for roleplaying, and probably discouraging for the wizard who wants to be smart.

I don’t see what benefit there is for a consistent bump in the middle of your dice results when you’re looking for success or failure,

I like being consistently good at stuff. Every time I flub it on like a 5 I'm annoyed. Like, this is my character's high concept why do I still have a huge chance of beefing it. With, again, little to no mechanics to succeed at a cost or fail forward.

I don't feel the same way when a dice pool betrays me. If I roll [6, 2, 5, 4, 7] in Mage I can look at it and go "wow, I guess I fucked up". Feels different when it's just 1d20 comes out with a 3.

But predictable mechanics mean that I can plan tactically,

You can have understandable mechanics with the stuff I described. And about as predictable as regular DND, where people can pass or fail checks.

Some of what I described would open whole new tactical fronts. Like, if you have spell sequences, you'd want to consider how far to let an enemy go before you really need to deal with them. Or if you want to try to plan around your wizard using them.

Anything where the spell doesn't fire instantly also opens new fronts.

I also forgot to complain how magic doesn't get interrupted in 5e. You used to be able to interrupt casters by getting up in their face. I see why they removed it- players don't like it, too hard, losing your spell sucks- but it removed an important depth.

All of this would kind of be dragged down by spells-per-rest, but that's a separate topic .

You can’t guarantee success, but you can influence your odds in a bunch of ways

5e has vanishingly few ways of influencing the odds. No flanking. Expensive aid-another/teamwork. No situational bonuses. Few resources to dip into. I'm assuming a party that's like levels 1-5 because that's where most people play, and without a lot of magic items because that's the default game assumption. Because the magic item rules are so thin, you can actually patch a lot of these problems with items. But that's a patch.

This may vary by DM, but I’m still actively engaged in deducing HP, AC, and any other relevant values about the things we’re fighting while it’s not my turn, and our DM accommodates us doing that.

This is extremely metagamey, and not very interesting to me. Some DMs just tell you the numbers. And even so, that's only so much you can do until you figure it out.

Compare Fate for example. You can defend someone else on their turn. Shit, I forgot, DND doesn't even have this concept. But yeah, in Fate you're engaged when other people are going because you might need to leap in to defend them, or spend a fate point to help them out. That's engaging with the game a lot more than "I wonder what their AC is?"

I think at this point we might have to chalk this up to we want different things from games, and have different preferences. Some people like mayonnaise. That's okay.