The Burning Crusade expansion has made playing WoW a lot harder than it used to be. Catering to your professions and your crafted gear is much harder now with all the business of primals and nethers. Being able to do the first raid dungeon requires a ridiculous multi step keying process. Being able to heroic 5 man dungeons needs revered status with the appropriate faction, a feat that could take casual gamers a long time to do. I can go on a bit longer ranting about these things but if you leveled to 70, you know what I'm talking about.
This makes you nostalgic for the old days when you didn't need to do much to get attuned for Molten Core and Blackwing lair. You didn't need to get keyed to do raid zones like Zul'Gurub and AQ20. The old content was the "good old days" and there were suggestions for Classic realms where people could not experience content beyond Naxxramas (and for sure this means the level cap will be stuck at 60). The Blizzard poster Vaneras has this to say about the idea.
The idea for having classic realms is not a new one… People have suggested or requested that Vanilla WoW realms should be opened, where the level cap is 60 and there is no content beyond Naxx.
We recognize the fact that some people prefer the pre-expansion content over the current content and as a result would like to revel in nostalgia, however the developers are planning to keep the game moving forward as they want the game to continue progressing and evolving.
There are no plans for classic realms at this point in time, so you should not expect to see the opening of such realms with the launch of WotLK.
wow.europe.com
While I too remember the good old days, it's time to live in the present. Besides, the gear and the money is much better in the Outlands! Also, by dropping the level cap to 60 once again for these realms means no new spells and abilities and 10 less talent points to invest in!