Depeche Mode could easily do 2 albums in 1 concert; Violator and Songs of Faith & Devotion. Violator only has 9 songs, Devotion 10 songs. That shouldn't put too much strain on Dave's vocal chords considering that Martin sings vocals on 2 songs from each album, so Dave only has to sing a total of 15 songs per show.
I could easily see them do a Violator tour--I would half expect they could do that this year, but the new album/tour name probably make that moot. I can't really imagine them doing a SOFAD tour, though. Even though I LOVE those songs, I feel like that album is a bit contentious among fans, and an anomaly in their catalog. Bands tend to just go to their best-selling album for these, and Violator is kind of obvious.
That said, I almost feel like I SAW a Violator/SOFAD tour, in the original Devotional Tour. They did a lot of material from those two albums. I think older fans may have been a bit put out they didn't dip into their earlier stuff, much like U2 when they started Zoo TV.
Sadly, I completely missed out on the Alan Wilder era of Depeche Mode, so the idea of those 2 albums is more of a dream concert for me, as Peter Gordeno & Christian Eigner will never replace Wilder.
Devotional was the first time I saw them. Saw them twice on that tour. Funny thing is, the second time, Fletcher had apparently left the tour due to mental stress, or anxiety or something. I mean, Gahan was literally killing himself with heroin, Gore was, I think, well on his way to being an alcoholic, and Wilder was shouldering a lot of the burden keeping things going....but the guy who kept busy clapping his hands behind the synth was the one who had to leave. So I officially saw the classic 4-man lineup once. Man, I wish Wilder would come back.
Oddly, for as good as the video from that tour was, I remember being underwhelmed with it in person. Didn't know enough of the pre-Violator stuff, seemed too short, and the lack of live instrumentalists seemed weird to me then. But it was classic, no doubt.