Yes they did, it was just a level gate instead of a story gate. The only difference is that a story gate requires the completion of handful of extra content.
Given that it would have made absolutely zero sense to end up in Ishgard without having first gone through the events in 2.1-.2.55, I can support people needing to go through that little bit of extra content.
You're right, having an NPC you can talk to that skips you right ahead to the first 3.0 quest wouldn't make a lot of narrative sense. Fortunately, the people that would use it don't give a shit about the story. It's a non-issue.
And yeah, there is a level gate for the new content in WoW, but that's literally it in terms of content gates. I got my guy to level 70 like two days before WotLK came out, didn't do any of the quests or raids in Cata, but was still able to go fuck around in Northrend at launch.
Nobody is advocating for getting rid of the level requirements of HW stuff, but there's a gigantic gap between "letting people instantly level their character to fifty so they can do new content" and "letting people skip hours of subjectively boring story stuff so they can do the new, populated content."