Can't get enough of blowing stuff up personally. OP's concern may stem from the unrealistic expectation of having a decade's worth of content crammed into a game that isn't even a year old.
Beyond that I think there is also the reality that right now running flashpoints can be boiled down to 30ish minute "spacebar/trash-skip/sometimes even boss-skip fests". When someone with 2 hours to kill can run 3 flashpoints with a bit of time leftover for BH dailies content can grow old a lot faster then when it'd take a over an hour per flashpoint to work your way through and polish it off. Also negates the feeling of accomplishment.
I think they may also seem a bit underwhelming given that all existing Hardmodes are tuned to an entire different gearing paradigm. The combination of Black Hole gear, Augmenting Everything, and passive stat boost relics mean two weeks into 50 you can be geared to where hardmodes pose very little challenge (and that's assuming youa ren't grouped with 3 established rakata-campagin geared group-mates). When you can basically muscle your way through content you might have had to finesse before, it takes some peril out of it, and therefore may also make it seem old-hat much faster.