an assassin who deliberately targets the party isn't a random encounter because by definition, it's not random. It's intentional. That assassin has a specific agenda.
I'm puzzled. I've always assumed that the "random" in "random encounter table" is a metagame descriptor, not an ingame one. Ingame, all those NPCs generated by random encounter tables have an agenda, and are not just wandering the gameworld acting in a random fashion.
For instance, in a traditional dungeon, if I roll an "orc" random encounter, and the PCs have just finished beating up on some orcs, then I (as GM) would present the randomly encountered orcs as relating in some way (tribal allies or tribal enemies, depending on what seems like fun) to those earlier orcs.
[MENTION=6680772]Iosue[/MENTION] had some interesting posts on this issue a month or two ago, in a thread about GMing OSR-style.
Random tables are useful tools to add verisimilitude when used properly. Sometimes plans are wrecked or altered by pure chance. An invasion fleet sunk by a freak storm for example.
A random encounter table that serves to illustrate the local setting is fine. Random weather is fine. Bandits trying to rob the PCs randomly is ok, that's what bandits do. Having someone try to kill the PCs specifically just because a table said so? If the assasins are competant that should be an unprovoked and campaign ending TPK.
I don't use random encounter tables in my current 4e game, because I prefer a Burning Wheel-style approach to my game: every encounter is conceived of by me, in relation to the unfolding events of the game, and deliberately placed.
But in the past, when I have used random encounter tables, they've included everything from assassins to demons to zebras.
I don't see why assassins are any more problematic as encounters - random or otherwise - than demons or zebras. If they will lead to a game-ending TPK that's an issue of encounter balancing or action-resolution mechanics, not the basic encounter concept. When Wolvering is attacked by ninjas, for instance, it isn't a TPK; and Conan survives surprise attacks too.
if my party is seeking to bring down an Orc warlord who has gathered a great warband of goblinoids then I should bloody well have to deal with scouts, patrols and guards. Whether that dealing involves combat or invisible flight is up to us as PCs. On the other hand, if the entire army forms a corridor to let us saunter up to the final encounter which is exactly balanced to be the level appropriate XP total for our party as a "Hard" encounter...
There are such a multitude of ways that this scenario could arise and unfold that I am not confident to say anything of a general nature. For instance, in LotR (in both film and book, though the film exaggerates it more), Aragorn comes up with a plan to distract the bulk of the army so that Sam and Frodo can sneakt through a corridor to the final encounter.
There are also a multitude of ways the "scouts, patrols and guards" aspect could be handled - from a whole swag of individual "easy" encounters, to being rolled up into a single Stealth or Survival check.
No, I'm not sure how I could have conveyed that impression. In fact the successfull collaboration between the GM and the players is key. Or rather the characters. The world advances on it's own agenda, as influenced by the PCs actions. If your preplanned story arc had the Duke plotting to take over a harbour town and the PC actions cause him to change course even though it disrupts the intended plot, that's fantastic. If you stick to the original plot even though it no longer makes sense then....
A Fate-style or BW-style game doesn't have a pre-planned story arc, nor a world advancing on its own agenda, so I'm still not sure how it fits into your conception of TTRPG vs WoW.
That sort of game has PCs built with rich story hooks for the GM to be dragged along by; and the plot is not pre-planned but emergent from choices made by the GM about encounters that will speak to those player-authored hooks. Much of the gameworld backstory is generated at the same time as the game unfolds, in order to maintain the pressure on the players and as part of narrating consequences in the course of action resolution.
In this sort of game, it would make perfect sense to have the orc army form a "corridor" through which the PCs can pass to the final confrontation. If the ingame explanation for this is not obvious (eg "Lord Throg has been expecting you!"), then discovering it can become part of the game play. (A variant on this second option is that, because of a session break, or something else becoming more interesting, everyone just forgets about the mystery of the orcish corridor, and an explanation never gets authored. My 4e game has plenty of these dangling, unresolved plot threads. The Burning Wheel Adveture Burner includes advice on how to catalogue them and then use them to kick-start new scenarios and campaigns.)
It is metagaming to never have an Ancient Red Dragon just swoop down and destroy a first level party. But it's not intrusive metagaming
This particular tangent was started by a remark that a certain approach to encounter design and world-building was GM metagaming, and that this was objectionable.
If, now, we are ony talking about "intrusive" metagaming vs "unobtrusive" metagaming, does that mean the objection has evaporated? Because what is intrusive is surely in the eye of the beholder, and up to each individual GM to manage as suits his/her table.