Just as a side note, he didn't say he was bored playing, he simply said he had run out of things he could do on a limited, erratic schedule and was looking for other ideas.
As for me, I started to feel this pain as well once I had ten level 80s on the same server (9 Horde, 1 Alliance that started as a spy 'toon and got leveled when I ran out of alts). What I noticed after leveling the Alliance alt is that I had typically blown through the same zones over and over and done the same quests on each of my other 'toons. I took a look around in Northrend, and discovered that what I really enjoyed was the leveling experience itself and the Warcraft lore bits they carefully put into quests. It sounds like you're the type that enjoys that as well, to some extent. So, when everything is quiet in the early morning, I'll spend an hour or so on a different server, on a random lower-level 'toon, just slowly questing.
I've made a wide selection of 'toons in specs I don't typically do on my mains (Enhancement shaman, Frost death knight, Shadow priest, etc.), and I'll take one and do a bunch of quests in one area and take the time to read all the text, read the lore, read the NPC's reactions, all that work that Blizzard put into the game and a lot of people ignore. I don't do this with the intention of getting them to max level and using them a lot, just as a way to try and experience every quest in the game, eventually. I am going for Loremaster (interrupted by the Shattering, bleh) on one single Horde 'toon, and using a bunch of random-level Alliance alts to experience all the quests on that side.
If that appeals to you, it's quite easy to do, and very non time-consuming, especially since you don't really have to have the intention of fully leveling them. If not, you may have hit a wall. Either way, once you actually finish that (probably take quite a while), unless your schedule settles into more regularity, that's probably about all you can get out of the game. Also...
We have been owned, I do believe. Lord, I would wet myself giggling if I could combine all of my alts Voltron-style into some kind of giant monstrosity. Shooting lightning out of one hand, fire out of the other. Firing arrows out of the mouth. Hearing the blood elves whine like it's going out of style every time I stepped on them as feet. A dancing troll as the head. Of course, the gnome mage would have to be the crotch, but that's just the Horde in me. Kick my Voltron in the crotch, hear the gnome death sound. Fantastic!
Screw this, good luck to you guys, but I'm going to go train my Goblin engineering up. If Cataclysm rolls around and Azeroth hasn't been taken over by some kind of huge robot made of steel, fire, and auction houses, I've probably gone and blown myself up. Either way, I'll have a whole lot of fun.