Noobs is an Operating System Chooser ! If additional OSes want to be added later then it is not feasible without starting afresh..
BerryBoot is multi-boot with the flexibility to add/remove OSes
IMO Noobs add more confusion and though a good "idea" for a new user it has limited value over swapping Single OS SD Cards and learning how to write an .IMG File
To a large extent, I agree with you. The areas in which I don't are (1) the RPF has more control over NOOBS than BerryBoot (and note that I use BerryBoot...but I use it on Cubieboards!) and (2) one must consider who the target user community is for NOOBS. It isn't for people who have long experience, understand image files, and are comfortable manipulating the system(s) in often complex ways. NOOBS is a way for the true novices to get their feet wet. It is also *an* answer to a lot of the early problems that people had with the Pi.
So..."standard" (offline) NOOBS with only Raspbian. No issues. NOOBS Lite for situations where there is some way of connecting the RJ-45 jack to the world. No issues. Beyond that, having a way to download or create a NOOBS card that is *not* on the main download page, for the use of those that want to have NOOBS features for themselves or other people they help so that it doesn't confuse the real beginners is, I think, the way to go.
I would slightly favor an arrangement where one could download the "standard" offline NOOBS and then go to a supplemental page that would permit downloading add-on OSes so that one could build a semi-custom "NOOBS" card by the selective inclusion of hand picked OSes. That way, the choices could be even wider than they are now, since different groups could build packages of their chosen OS that would work with the core NOOBS download and make that package generally available. But those addons should not be where a random new user is likely to download and install them by mistake.