HR dying in place of Iris was not only a bad cop-out, but also a punch in the gut for everyone who even remotely felt sad during Iris's (admittedly well made) death at the end of the last episode.
Also, no one even cared at all for his death. They were all happy and smiling and willing to help the guy that murdered him a few hours after the fact. They even get "angry" at the girl who loved him for not wanting to cooperate.
Then they try to help him anyway, with the Power of Friendship, and surprise, the bad guy is still bad. Then a very short, very disappointing final battle happens, where Barry somehow comes up with the idea of hijacking Savitar's armor and destroying it from the inside, then Barry gives him a punch and walks away. Of course he's still conscious, because of course he is, so Iris shoots him before he kills Barry even though the fastest man alive is proven to be faster than any bullet, as proven in the episode "Attack on Central City" a few months ago.
Then everyone realizes it's time for the obligatory cliffhanger, and Barry just walks away. "See you in an episode or two at best!"