No, this has to be clarified. [any1 move to discussions or so]
(When I write "you" I mean everyone who feels like theres not enough to do for adventurers)
The topic is more difficult than you may think, and as gizmo already hinted, it has already been adressed some times before. Now first off: How does a person get Designer? Most people think it's only about excellent building skills, but in fact that's by far not everything. Another important thing of it, is acting in the interests of the server, now that may sound weird, but what it means is: The official main goal of the server is simply building middle-earth. But actually it's rather "Building Middle-Earth
together". There's some other Middle-Earth recreation projects happening out there, but most of them have a far smaller community, and thus for MCME not only the building aspect is a great deal, but also the "together" part.
Now for how we tackle the task of trying to get everyone involved: Especially for Adventurers we have and always are seeking for possibilities to hand builds to Adventurers. The big problem is, that this comes with some limitations: As everyone is capable of joining the server and thus get all Adventurer permissions we have to make sure to choose these permissions so, that every kind of abuse does not greatly harm the server, but at the same time we want to offer as many things to those adventurers that want to contribute to MCME in a positive way.
Jobs. The most well known of these possibilities, with the awesome job plugin especially made by our developers we have a good control of everyone. Jobs are most practical if you need a large number of something (long road, many houses), just because setting up a job includes some extra work, and if one person can do it in five minutes it's just way over the top setting up the job kit, waiting until everyone got Teamspeak set up and so on. Furthermore there should be some people online, as supervising a single person building is not so effective. [Note: The most precious thing on earth especially for staff members is time]
Now once there were about ten adventurers online when I asked whether someone is up for a job. Only one Guide and one Artist said yes. Or an other situation when I started a job and literally noone joined. I don't know how to solve that when there's a job nobody cares, but when there's none, everyone complains about no jobs. There's also the critique that with jobs we always only do the boring stuff. Two remarks on that, first there's some things that are simply easiest and fastest to be done with jobs (roads, glaciers), second, the area between boring jobs and overstraining jobs is very thin, and as in the end the build quality should match a certain current standard, and as simply not everyone is equally skilled in building it is practically impossible to offer jobs that suit everyone.
You're from Australia, that's in fact a problem, afaik since wolli resigned there's no more australian designer, and most of us designers have to work or got to university and thus can only join in the evenings. There's no real solution to that I fear.
Plotworld. Plotworld is a separate world on the main server that can be accessed with /mvtp plotworld. It is a fairly new feature and a main reason that we did set it up was to give Adventurers more ways to participate in building. On Plotworld mainly two things happen: Freebuilds and Contests. In the last weeks up to about seven of these were running simultanously and for most of them you can simply tune in and and start building, without any need of registration or similar. At the moment the Pelargir Boat and House Freebuilds are open, and a Contest for the house of the Faithful. If you make a house in the Pelargir House Build it will get implemented into the main map with 100% certainty, IF it is good in the end, which mainly means you read the feedback that staff gives you on your house and accordingly adjust it. Again, Plotworld was mainly created for Adventurers!
For Moria we plan on relying on Freebuilds and Contests to a great extent (note these things have not been definitely planned). We plan on giving most of the corridors and smaller halls to Adventurers+ to build, similar to house freebuilds, and that'll maybe be the biggest Freebuild ever.
Build days. You wrote that there is often build days, unfortunately that's not the case. Even more, build days also dont last the whole day, but only some hours, they are mostly just big jobs.
ThemedBuilds and getting Artist. In the end, if you want to get more involved into building, and you have the feeling that you have or can gain the skills needed for it, you should definitely try to get Artist. This mainly includes two things: Making ThemedBuilds on the Freebuild server and apply with them, and being around on the main server, participate in jobs and Freebuilds, and just generally make your name known to staff members by being an active and positively perceived member.
I hope this explains the staff members point of view and satisfies you, if not, I at least hope you see how tricky the topic is, and that we really do care about it.