To be honest, one of the most lazy and detrimental aspects of the current game is the constant duplication of content which is continuing with the introduction of flex mode. To couple that Blizzard invalidates most of the old content it produces with catch-up mechanics, although this has been toned back to some degree with the removal of mid-expansion 5 mans. What I don't understand is why the old model, a continuous spectrum of unique content, wasn't working. To better illustrate my idea, lets look at the game back towards 2006. Going from a player who has the least amount of time and dedication to play to the most, it might look like this:
1. If you really lack a lot of time to play, leveling up through the large and expansive world is basically your end-game. It takes at least 10 days played or 240 hours to reach level cap for the average player, so you're looking at almost 2/3 of a year for a person who plays an hour/night. The leveling back then was challenging so it could reasonably be end-game for some people, but also quite interesting for anyone familiar with warcraft lore and it's characters. The lack of flying mounts as well as non-linear quest design actually made you want to explore the entire world. Also meeting friends and enemies was much more common given the length of time to took to level, which makes for a much more immerse environment. All this factors serve to show why leveling was actually a captivating source of play for people with a heavy work schedule and not just some obstacle like it is today.
2. Ok,so now we have people who have the time to make it to level cap, but maybe still have other commitments, so they can't make weekly scheduled raids or that sort of things. So what do they do with 2-3 random hours. Well if they aren't quite the social type, they can farm materials such as felcloth, which could be crafted into fairly decent upgrades. Some items like Robe of Winter Night could easily be better than molten core gear but with a significant time investment farming. Most of the crafted gear is flat out terrible today and the materials often come out of raids anyway. This also applies for farming consumables. Second there is PvP. Great BGs like Alterac Valley used to be an interesting mix of PvP and PvE. They offered something for everybody and the epics that the BG factions provided at exalted were extremely good. Great gear that anyone with a few spare hours here for there could effectively get with enough time invested.
2b. I made this a whole separate section to highlight how great the old 5 mans were. Blackrock Depths is not even a max level dungeon yet it is has more bosses than ToT LFR, is arguable more lore rich, and could potentially take longer depending on your group. Honestly nobody should be upset if this is there end-game. The great size and variety of endgame dungeons in vanilla can't really be understated and although they often dropped bad or useless items, there were occasional items like Felstriker and Ironfoe that were often superior to most raid loot in the game, something that was warranted by the number of runs people could spend farming this item. Getting a perfect pre-raid set took a lot of time and effort. I don't really see how running LFR over and over again is really any different from running the wide variety of vanilla dungeons for some great items. The only real difference is that they often aren't purple.
3. Ok now lets say you have some time to raid, but only really on the weekends with some friends, nothing too serious. You can spend a lot your time doing 1-2b, but also you have 20-mans, ZG and AQ20. These instances provide yet another level of content as well as access to important reputations and enchants that allow you to improve your character. You can also get really rare and epic mounts, however with a very low drop rate. This is the easy mode raiding; the flex raiding that accommodates guilds who don't have the greatest of players or enough to make a 40 man.
4. And finally for the 4th tier of content we have full 40 man raids. See how this is only the last tier of massively multiplayer content and not the sole reason to play the game? Even in this "final" tier we still have a continuous progression in difficulty. The smooth (or sometimes not so smooth depending on how many times you wiped on Razorgore) transition from Molten Core, to BWL, to AQ40 to Naxx, provides a wide, wide range of content for players of most abilities and time commitments. The range of difficulty from Naxx to MC is literally huge and was proof that WoW provided something for literally everybody.
So again I have to ask "Why do we need to duplicate content 4 times?" Why instead can't we just create unique content for everyone that was done 7 years ago. It was the time of the game's biggest growth, and it wasn't just because it was new. It was because there was something for everyone and literally no matter how far you got in the game, there was always more to do. Today we have even the most casual of players clearing all of the unique content in the game in a matter of days. No wonder people are getting burned out and unsubbing. No wonder long standing guilds are collapsing. The common retort to this is that designing content for the very highest of endgame is a waste of developer time and money. First of all as I pointed out in my post, that high end content (i.e. Naxx) is only an extremely small amount of the overall content that players experience. Also, the content is still necessary to provide this continuous spectrum even if not many players and going to see it. This overall design goal is important and developers should recognize that. Thanks for reading.