The original Saints Row was basically a GTA knockoff, albeit with much witty banter, and it didn't have any customisability.
SR1 was plenty customisable, arguably even moreso than SR3. You could only play as a male character, you couldn't choose a voice (as the character had no voice), and you couldn't customise your gang (as the protagonist wasn't the leader of the Saints yet), but your appearance, clothing, vehicles, and other things were customisable.
I would also disagree that SR1 was wittier than the GTA games, I thought the attempts at humour in SR1 were really poor. Half the time in that game I struggled to tell if it was trying to be serious or humorous because it was so awkwardly written. The radio advertisements were the worst, they came across as really forced. SR2 was when they finally nailed what the games were about, and the huge improvement in humour over the first game was a big part of that.