I don't really have a strong opinion either way.
I really would like to get the Challenge Mode armor (or armor like it) on some of my characters, but timed runs are not my thing. I'd rather see hard dungeons with a chance of dropping awesome looking pieces of gear.
As far as flat out buying sets of armor that are more detailed or have special effects on them compared to standard tier and pvp armor... I don't mind it as long as there are Challenge Modes and Achievements that also reward similarly detailed armor.