For all the pretensions of 'quality' in Saints Row IV, this was absolutely the least fun I've had playing a game in the main series (never played SR 1, so take that with a grain of salt if you like).
The writing is decent, the missions are inventive, but when it gets right down to it there's just nothing spectacular about SRIV. Where's the moment when you realize the Boss is about to give Worf face cancer? When does the Hulk make you drive around in a convertible with a tiger riding shotgun? When am I going to meet and gain the trust of a new, absolutely ridiculous lieutenant like Zimos locked up in a sex dungeon?
In the end it just felt like an extended, official piece of fanfiction. Put all the old characters in an enclosed space, make the main character bone/explode/shoot/shockwave whoever you want, spank the monkey, repeat. I never felt an attachment to anybody in the game except for Pierce and Zinyak (I was surprised to realize I no longer cared what happened to Kinzie, but she's really changed from the 1337 haxxx0r who IRL hides under the table at a pancake house), and for all the talk of 'inclusivity' what that really seemed to mean was that nothing was particularly fleshed out and that none of your choices mattered. Maybe it would have been interesting if Gat was homophobic, or Pierce was totally gay or Kinzie wouldn't sleep with you unless you were part cyborg. In fact, I can't recall making any choices in the game after the white house mission, and never any with a lasting effect aside from when I want to buy X, Y or Z.
So, yeah. Disappointed.