A few disc issues/aspects---bust a spoke and you have brakes. I used to do a ton of loaded commuting and every now and then I'd hit something immobile and unjumpable. Slamming a loaded rear wheel into a curb or the edge of a new pothole has expectable results .... and I don't care how much you fiddle with spoke tension, at some point you are going to have to accept that you need to open the brakes and be glad the tire isn't hitting the frame. With discs, you don't even need to try to true the tire (I'd suggest it though .... )
Also ... how many of us kept careful calculations and took precise measurements of the stresses on spokes, hubs, brake bridges, chain stays, fork blades .... No One Cared. The only reason people mention these things today is because they don't like discs.
Discs weigh more? The Only time a few grams rally matters is if you are racing someone in a situation where bike weight is unregulated .... what? Outlaw Street racing for pink slips on Bikes? otherwise, ... pretty much every single one of us (except LongJohn) could lose a few grams in body weight .... or use Tubolite tubes ( ONLY $40 each---a Bargain at a quarter of the price.)
Not saying weight doesn't matter. After five flats, I had to ride my lightweight CF bike to a job meeting, and I can tell you, even being a quarter-ton overweight, I could feel the 10 pounds less bike weight on that final hill. But how many people wonder about how much better we'd ride without all that heavy paint weighing us down?
Simplicity? For sure. In fact, my work bike has mechanical discs (All the Weight, No Better Stopping Power) because if I am out on the road, I can fix a cable but not a broken brake line or leaking fixture. But my MTB has hydro discs and has never let me down. I mean, if simplicity were all that, we'd all ride single-speed. We accept weight and complexity in return for performance, comfort, utility.
Anyone who rides a lot of fast descents would probably like hydro discs (if they would be honest enough to admit it) because of the ease of one-finger modulation and basically fade-free performance. Someone who rides in the pacific Northwest might enjoy knowing that that half-second of sphincter-clenching while you wait for the rim brakes to squeegee away enough water to make that life-saving panic stop is a thing of the past now (that was my specific motivation.)
Shoot, particularly in the wet, I can lock up my wheels with rim brakes (and I have done it in the dry too) so a huge boost in braking power isn't the issue. And, obviously I was never killed while waiting for the brakes to grab (came pretty close a couple times.) So, as far as absolute engineering, disc brakes are unnecessary.
The next question is ... are they a deal breaker? As I see it, they are as reliable and as effective as any other type of brakes, and they are taking over the industry ... so either lay out the money for custom, buy a bunch of frames now and save them, (better get some spare bottom brackets ... ) or just go with it. I don't see the very lightest bikes from major manufacturers weighing a lot more ... weight isn't an issue because the bikes can be lightened in other areas anyway ... and I don't hear about all these disc-brake bike failures (only the same deluded whatevers talking about how they break three frames a year with their Awesome Watts, of how the fork failed --- a hundred miles after they crashed head-on into a wall flat-out (but it Looked fine) .....
So, it would be a matter of personal choice except the industry is moving away from rim brakes ... so what?
A one-piece Ashtabula crank is simpler, but I didn't refuse to buy bikes with three-piece cranks, or cotterless cranks, or press-fit (though I convert all of mine to threaded.)
Not worth the headaches, to me. I buy what is being sold. I find the closest thing to what i want at as close as possible to the money I want to spend and do whatever seems right.
Seriously, though .... people who Will Not have disc brakes don't have to. Just be smart and buy ahead.
I expect my CF bikes to last as long as I do, and my steel bike or my Al bikes with CF forks .... almost eternal. I have long wanted a Ti bike, and again, I see no reason why i couldn't ride one for the rest of my life and sell it after I died to someone who could ride it another fifty years---there are bikes from the '20s and 30's on C&V sites. Just load up on parts now.
Me, I will go with the flow. I can believe that a person would not enjoy riding a bike because it has disc brakes--but I am not that person. Put me on a bike and I am smiling.
But then ... I shave with the lowest-cost plastic store-brand budget razors I can find at the supermarket. Some folks got Standards .... I get it.