You seem to be presuming that editing MusicBrainz is a serious goal people are trying to achieve, that they’ll be willing to work towards despite a bunch of obstacles. (Which, given the amount of work to enter a release, must be somewhat true for everyone here).
So, I’ve had a MusicBrainz account for a long time, but I’ve only recently (since December 2014, I guess) been active. That was because I finally decided to re-rip my entire music collection, which had previously been in Vorbis and hand-tagged. And also to deal with the huge pile of disks which hadn’t been dealt with at all… So I guess this wouldn’t have applied to me (since my account wasn’t new), but I certainly was a newbie editor back then.
So most of the discs, I think (did not keep stats—and do not feel like it’s worth the work to gather them), were already in MB. Some were trivial to find (discid), others take some searching (and then adding disc id). So selecting 15 releases to add would be annoying, but not insurmountable.
Now, I’d enter in 15 releases and… still not useful. Can’t tag with only an artist and name (and this is presuming the tutorial understands these are classical releases). And they’re not useful to MusicBrainz either — that is no where near enough information to identify a release. At least not a classical one. (E.g., because the title is often just the single symphony that is on the release, and especially for popular symphonies a given orchestra and conductor will play and record it many times). It’d take until step 6 until those were useful entries in the catalog, as they’d at least be (hopefully) identifiable. And hopefully I’d kept them separate on the shelf, else I might not be able to find the same ones again…
However, despite entering 15 discs, and waiting several days for forum replies, I still haven’t been able to rip a disc yet. So the goal has been thwarted so far.
I’m not sure how you enter track lists (7) without recordings (9). I thought the schema didn’t allow that. But adding the track list is, depending on release, a bunch more hours for 15 releases. Same with cover art. Still haven’t gotten to rip a disc yet, though, many days & hours into this process. After adding the discid (14), finally morituri will allow ripping the disc (which is good, otherwise it’d be hard to add AcoustID data).
MB still isn’t useful, though, after probably a full day’s work spread out over two weeks (remember, goal was to re-rip music collection). Could just come up with a local tagging solution again, seems like much less work.
Anyway, and then step 15, do it again.
The goal of ripping and tagging my frist release can’t actually be accomplished until step 18 because until then, I’m not able to enter the works (and this composers, lyricists, arrangers, etc.) or the performers, recording location, soloists, etc. (the recording ARs). That’s at least two or three weeks of elapsed time and two full days of work (and probably a similar amount of work for existing users, who have a lot of stuff to review).
A tutorial would be useful, but I think it’d probably be better if it guides you through adding one disc, and at the end of it you have something useful for tagging (and also for the database). And you can stop early (say after the tracklist/recordings, before ARs) and still have something useful. And you’re welcome to go through the tutorial again for the 2nd disc, or third (but probably won’t need it again). Each time though you do a reasonable amount of work and actually accomplish the goal you started with.