Re: 8 years of no Batman or Bruce Wayne, and NO ONE could pick up the trend?
What I really enjoy about the LOS connection between Begins and Rises is that it makes Begins feel like a part of something bigger and more epic, which makes the overall tale being woven in the trilogy feel more cohesive. There are certain moments in Begins that I can't help but watch differently now, like, "When someone stands in the way of true justice, you simply walk up behind them and stab them in the heart."
And not for nothing, but Ra's' line about his "great love" always felt like they were keeping the door cracked open for Talia to enter the story if they chose to go that route. It's a one-off moment of backstory in Begins that has no further payoff or relevance to the plot. It stood out to me even back then.
I was never super excited about a LOS return for a third film though- there are definitely a lot of ways it could have come off tacky and pedestrian. Thankfully that wasn't the case though, they sold me on it big time.