1) Burning Crusade is now old content, just like the original game. The fact that it's easier now doesn't lessen the accomplishments of those who did it when it was difficult. It just makes it so that those who do wish to see old content will have an easier time when they go back to experience it.

2) Some of this change was also to balance it with the way the classes have been changed. Abilities have been changed and shifted around in ways that would've made it extremely difficult for any raiding guilds looking to finish up this content over the next month before Wrath of the Lich King's release. Some dps have less crit, less mana regen, etc. The encounters would've simply been too difficult under the new 3.0 systems.

In the end, I don't think the encounters are actually going to be much easier, if at all.