Guys, this just a matter of perspective. They're not really dependent in the sense that one affects the other - they just affect how you're describing the difference in ACs. One point of view is not better than the other. The difference is whether or not you're just looking at hits compared to the other case vs looking at the whole list of outcomes (misses and hits together). Which one is the better perspective to pick usually depends on the argument you're making and the impression you're trying to give. A +1 to hit makes for a 100% increase in productivity if you would have only hit on a 20 but only affects 5% of the rolls. Which impression are you trying to give - that it's a whopping increase (100% YAY!) or an infrequent case (5% of trials, Boo!)?
It's not just perspective, though, or "what you're trying to argue", that's a bass-ackwards way of looking at it. It's about
trying to derive useful information from it. And knowing that it really does result in a more significant in the number of hits, over time, than it might appear from the straight-die-mod percentage alone is more useful than just knowing the straight-die-mod percentage.
A key problem is that the current model is a different form of boring. Right now we have "bullet sponge" enemies, so named after the FPS (and third person shooter) approach to difficulty where you need to empty an entire clip into the enemy to get them to drop.
I don't think it goes quite that far, but yes, 5E is a system where monsters (and to a lesser extent, PCs), have a lot of HP, and it's hard to bring it down. In 4E they had even more, but you could do a lot more damage a lot faster, in general, and you minions to break things up.
I've literally never heard anyone praise 5e's combat.
I mean, that's not true. You've been on this messageboard a long time, and loads of people have praised 5E's combat. Indeed, people praised it a huge, ridiculous amount when 5E came out, so if you were around then, and you're saying that, well, buddy, that's some real memory bias in action. People still regularly say stuff like "5E has good combat" or "my group likes 5E's combat" or the like. So that's a weird claim.
If you said "I see far, far less praise for 5E's combat than 4E's", I'd have to agree. Even now, people outright praise 4E's combat more 5E. Equally, if you said "people have an awful lot of criticisms of 5E's combat", that's very true - more than for a number of modern TT RPGs. But no-one praises it? Man what.