Re: 8 years of no Batman or Bruce Wayne, and NO ONE could pick up the trend?
Bane wasn't doing it for Ra's, so much as he broke Batman and carried out Ra's plan on a grand scake for his own benefit. When you look at Bane's reaction to Bruce's "You were excommunicated by a gang of psychopaths" and take it together with visual cues like the jacket grip Bane shared with Ra's and the full story about his time with the League, it's apparent that Bane's jealous of what Bruce had with the League. Ra's had rescued Bane and Bruce from similar circumstances, but threw out Bane in favor of Bruce. Then Bruce threw away the opportunity he'd been given by Ra's. On the side, there's Bane's line to Daggett about power that indicates he had some stake in the social revolution.
Now, if Bane tried to build a mob of followers juiced on a Nolanverse take on his classic Venom, I'd say it was more a repeat of BB.
"Consistency is the last refuge of the unimaginative." - Oscar Wilde