I understand all the points here, but it's not that cut and dry. It depends on whether DT is trying to put out "80 minutes of the best possible ideas we've had between xx/xx/201x and xx/xx/201x", or whether they have a conceptual idea of what this record is going to sound like and try to get to as close to it as they can.
Allegedly, Gene Simmons is threatening to put out a six-CD box set of all his song ideas that he's had over the years, and while he hasn't mentioned this in a while (it was first mooted around the time of the Kiss box set) his point was, I have all these ideas that either don't fit on a Kiss record, or at that point Paul (or whoever) had something they wanted to say. Whether any one person thinks those songs on that box set are "better" than what appeared on the various Kiss albums is irrelevant. The record that came out is the statement the band wanted to make.
I can't help but think that if that riff or that vocal line was SO good, the band would have made it happen. These are our heroes, in a sense, and I wish we'd trust their judgment more in terms of their output. This is what they do, for a living. They have been able to not just make do, but thrive on making music for a living, which we all know is not an easy thing to do.