They weren’t really that hard, even at release. Just compared to the Wrath heroics. My issue with them was more that I didn’t like the aesthetics. The themes of the Wrath dungeons I thought were great, and I did sooo many of them thanks to RDF. I just loved them. Great variety. So it was a wonderful combination of fun dungeons that were easily accessible. Cata only got half that equation right. For me, anyway.
MoP dungeons I remember enjoying more though.