I think this hits upon my main nitpick about multiverses. I have no problem with the concept overall as long as the publisher(s) in question use those alternate universes.

For example, Earth-1, Earth-2, Earth-3, Earth-X, Earth-S, all of those are fine for these universes were shown or referred to on a nearly consistent basis by DC for a number of years. However if you do an Elseworlds one-shot where Alfred becomes Batman instead of Bruce, does this really necessitate the establishment of a whole separate universe to support it?  One-shots, imaginary tales, imaginary crossovers, stories that may only be referenced once, maybe twice even, I don't see the need in engorging your multiverse in such a manner to support these stories if you are not going to showcase these alternate realities on a more consistent basis.

On the other hand, Marvel from the start was never set up to properly support such a concept. Their sliding timescale undercut one of the reasons for having such a multiverse in the first place (was Tony Stark injured in the Vietnam war or the war in Afghanistan?)  Plus, I never thought of Marvel having alternate universes, just the same universe enduring an alternate timeline (a view re-enforced by years of X-reading). Again, if they were to showcase such an alternate universe on a consistent basis, that would be more acceptable to me. For right now, I only consider the Marvel multiverse to include the original 616 universe and the Ultimate universe for those were the only two published in such a manner. The rest were just associated with any number of singular events or story arcs (unless certain alternate characters proved viable hits which is where you get Spider-Gwen or my favorite, Mayday Parker Spider-Girl)