To be fair, it was the combination of both that made Bon Jovi sound as excellent and amazing as they used to do. But even the last albums with Richie were artistically and musically dire. And his Aftermath album also lacked some of the depth and blues I had hoped to hear from him again. It was essentially Jovi music with a bit more guitar.
I absolutely agree with you that him leaving has made the band's music even more bland and that his input on guitars and vocals could've actually lifted some mediocre stuff from THINFS to being some good tracks, but overall they've just both gone way past their prime.