@populus (and somewhat @iamreallysquall):
The main reasons I don't is because:
1) it's a BIG headache to get people into a guild where notoriety / reporting isn't a problem (particularly for people who are participating but are also idiots)... and limiting those who participate to those who either aren't idiots (or at least limiting it to those who the event host knows they can trust) would be limiting the amount of people who can participate very significantly. Even if you are playing with people you trust, it's still annoying to have some people noto blue, grey, green, etc.
2) it's extremely difficult to control a lot of event conditions (the only way to really control what participants can bring to an event is to gate them in as ghosts, which is also a huge headache). Even getting everybody to the right place takes time and effort--like herding cats.
3) a variety of things (e.g. capture the flag), are very difficult to pull off without some special mechanic or staff assistance being in place, EVEN WITH a lot of extra man-power during the event to referee, etc.
4) it's easy for people to grief (as Blaise said), and there's often no way to protect yourself--even from blue people who just jump in to wall of stone or steal the flag or whatever.
... I'm sure there are other reasons too.
The last time I remember aware of even a semi-organized team PvP event involved a 4v4 (I just happened to remember it due to Lightshade posting an image of it on the pic of the day)--happened a long time ago.
I'm Mistah T in there if you didn't know.
If I'm not mistaken, this happened after Flea had organized a player-run capture the flag (obviously putting a lot of work into it) at Bucaneer's Den that completely failed due to it requiring a little staff assistance and the GM involved had some Real life stuff come up that prevented him from showing up. After that had fallen through, lot's of people left, but some of us (we had about 8 ) decided "hey, why not do something else". We did, and it was fun, but as I said, even with that small group, it took a long time to get people into a position to start... AND we had the special twin tower CTF course. As I recall, we actually didn't do CTF--I'm not sure how else to reasonably do a player-run CTF outside of Rose's "Capture the Capital" type idea of carrying heavy ore from the other team's box to yours, or somehow ending the game after a single capture--and even then, it requires those who are involved to control themselves to play by the rules--limiting, again, the number of people who can participate. We were doing the simplest event of all: a team FFA. Probably took an hour and a half before everybody could organize themselves together to make it happen. Was it fun? Definitely. Why don't we do it more often? I think that I've made that abundantly clear.
I share that long-winded experience because I think it is illustrative of how it is fairly silly to expect players to keep organizing such events given our limitations, as well as WHY we don't see even small-scale player run events like this on a regular basis--especially ones that involve group PvP.
now, more @iamreallysquall
I don't know think mechanics governing events are or should be limited quite as much as you have made it out to be--In the T2A era, I never saw a chest that only allowed a particular guild (Urk) to put heads into it (and spit out Urk heads if they tried to put in their own)... yet we had it here. Why? because it made for a really neat event. Sure, you could have had a player sitting there all the time being the "head collector", but that's be way more effort than creating a simple "mechanic" on a chest that allowed the process to be automated. I don't hear anybody shouting NEA about that chest... why? Because it added value without touching the core T2A mechanics. What about other aspects of the Bloodrock Urks? As far as I can tell, there was no mechanic I was aware of that aligned monster AI with a particular guild; yet here it is? And I'm not aware of OSI providing a special region where a particular gulid could attack anybody without penalty... these are all "new mechanics" as you seem to be defining them. It's not very far from that what I'm talking about.
And I think these Urk mechanics are great--that's my whole point. I would like to think that Derrick & Co. is not opposed to a new mechanic for the sake of generating content to at least some extent. Obviously he has to draw the line somewhere, but the fact is that there is certainly a precedent here (using Urk as an example) for creating a system of mechanics that can be utilized by players to make for interesting content should tell you that it's certainly not out of the question (thank goodness). The core mechanics of the game are obviously quite untouched by the extra Urk mechanics--I think that's the important part.
And due to the minimalistic approach of staff involvement (which isn't a bad thing overall), I personally think that many of the cool events and things that COULD happen IF staff were personally involved, should be, in some way, made available to the players inasmuch as it does not open up big exploits, etc, for the sake of keeping this 15 year old game interesting. Read Derrick's quote in the OP. Re-read it. I think it's clear that there is some room for creating really neat event-specific mechanics on UOSA, at least in Derrick's opinion. And I think that's certainly the way it should be, especially for a game this old.
I'm not sure how you keep getting off on this idea that those who want to see more of this kind of content are trying to "Introduce more shiny pixels (rares) for a buy in of stuff that we have literally tons of on the shard to generate some crap that is going to sell for millions yeah i think not", and yet what I and others have suggested is pretty much 100% gold sink and redistribution. I don't know how to make that more clear. I'll try though, Here's an example: Everybody pays 5k to get in. The winner gets NumPlayers x 2.5k in a reward. The rest disappears, and everybody had a good time. Maybe the 5k buy-in bought the player a few basic supplies that they start with in their pack... you really think such a mechanic is outside the goals of the shard?, or that we would be introducing more pixels?
Staff, under era-accurate mechanics, can certainly do a TON of stuff. My point is that, given the amount of work it takes to do that stuff as a member of staff, and the fact that staff on UOSA are very hands-off, that I think creating a system whereby players can access some of that stuff in an unexploitable (and gold-sink) sort of way in order to create neat events and good times... what are the downsides here? We could talk about schedules and things--people logging in only for scheduled events and logging off... but people do that for player run events too? Furthermore, a system as I described that is player-driven doesn't NEED a schedule.
I'm at a loss for coming up with the downsides here.
Also, iamreallysquall, (and I'm not trying to be a jerk or anything, just asking because I really don't know how much you've actually tried and I'm curious what you have previously done)--what events have you hosted?