Sorry for the double post.
Not to answer Trev's question but as I said something similar I will answer from my perspective. This is filled with my usual share of guesswork and estimates and I don't work in the biz so please correct me where possible.
I think that cutting the line down (or for my argument's sake cutting the shared line titles down, you can still have Vertigo, Johnny DC, the video game licenses, ultimate universe, and whatever other standalone titles) provides a couple of potential advantages:
1) Reduce cost to get people to completely buy-in. This is not just money but time, space, whatever resource you have. Plenty of us old timey 80's comic readers used to essentially buy the entire line of a books back in the day (although I know John still does). If you have 25 main titles only, then I know personally that is manageable enough for me to want in on it all. I can swing 25 books a month via time, space, and money.
2) Completionist urge can't swing that pendulum easier. In any complete universe of books past 5 or 10 books there are going to be at least some amount that are not to your liking as much as others. I don't think there is a hard number but lets say that there are 3 or 4 that are "meh" and 1 you don't like. Well if I am already getting most of the books, I personally am more likely just to keep getting those other 4 or 5 so I can have that complete thing. I think most comic people have this urge to some degree and I know I have beaten it down, but in for a penny, in for a pound. DC has about 55 or so with the minis and all. At that ratio, there are too many meh books to justify getting them all.
3) More cohesive universe. Presumably with 25 titles, the editors can actually make the titles seem more consistent. I am pretty sure John has pointed out issues with the treatment of Superman in the new 52 and there are other times when even in my limited reading I am not sure it all adds up. Now maybe they could do this with the new 52 and are choosing not to for a variety of reasons (made up reason could be that two high profile writers/artists want to do their own thing and it just can't be meshed. You can't force either of them because of their high profile, I am sure we could come up with a bunch of other excuses). No matter the how and why, 25 would be easier than the current number of titles from either Marvel or DC. Maybe 25 is still too much. Obviously with 1 title, it is axiomatic that there is no conflict with other titles. At some point it becomes practically impossible to coordinate the titles and still get them out profitably (I would think but you computer guys always have clever systems so maybe you could make it so all titles are consistent and cohesive but how do you spin that many plates.
4) Talent management. I don't know about high quality, but certainly I think we can say there are only so many high-profile or big names in the comic business. Certain of them are not for hire so that knocks those out. Generally speaking, at least for now, it seems to me that Marvel and DC get the lion's share of those names. I imagine that this is because they can pay the most (but if there is a smaller publisher that pays more, please let me know). Some of the smaller guys can offer rights and control that you don't get at Marvel or DC. However plenty of those publisher are also doing work for hire where the artist might get profit sharing but not rights (Dynamite and IDW do many licensed propreties and isn't Top Cow work for hire?).
One artist can only do some many projects at once so with less projects you could theoretically staff every book with a high profile name. Only the most expensive people.
However this is entirely premised on the theory that the high profile creators are the best. I don't know that I believe this but it is probably true that the high profile people sell the best. I am finding great new people all the time.
To your specific question, I don't know about highest quality but it seems like the one title places do give you the unadulterated directed vision which likely speaks more to the cohesiveness concept. Terry Moore, Jeff Smith, Dave Sims, Thom Zahler, you are getting their perspective directly jacked into you. Now a 1 title operation has so many strikes against it that I don't think it is much of a practical model for any but the big names/singular vision. I think it is probably tough to get discovered by readers, you get no economies of scale or other similar efficiencies. Only a certain type can make that happen and by default the ones that do make it are going likely be special. I would probably advise trying to distribute a different way, look for new customers like Knights of the Dinenr Table seems to do. Also I would imagine that it is tough to pay high rates with a single title if you need collaborators. I don't think there is much profit margin in a single comic title. If you are trying to support 2 creators off that 1 title, you need to seel more than if you are supporting 1 creator off of the title. I think it really favors the one person operation for that.
However some of the smaller publishers do seem to have a better hit record with me. I like Red 5 and Th3d World and it seems like you guys give good marks to Big Dog Ink. Now I think Big Dog Ink books do have a similar vibe to them in look and feel but I think Red 5 and Th3d World seem to have titles that are pretty different in art and story. Bonnie Lass seems worlds away to me from Atomic Robo but that is just my take. I think the smaller publishers can really vet the titles they do because there is only a few of them (see my factors above). So even if the titles are not linked, they seem to really work hard on them. Not phrasing it well because I imagine Marvel and DC work hard as well.
This will never happen at Marvel and DC because I don't think they could make up the difference by cutting the line down that much. Marvel seems to have tried twice in my life to build sizeable little standalones, the new universe and the Ultimate universe. The problem is when you have that as a side to the main titles, the factors I list above are greatly weakened. If DC cuts the line in half, they would need sales to double. I think sales would go up but I doubt they would double. Therefore they lose money. Marvel would be cutting the line in 1/3 which they would never do. They are both now built on spreading the seed wide and catching what they can. Admittedly fewer titles means fewer creators to pay so a little savings that way but I doubt it is much as they probably lose some of the economies of scale that way.
Enjoying this discussion quite a bit. Glad to see the board get lively. Thanks to Trev, Boshuda and John.