Hi San,
Interesting questions! You might want a Big Data book after Algorithmic Thinking
1. I think it's more important than ever that we get our algorithms and data structures right. Computers are faster than in the early 2000s, but data has exploded relative to that speed increase. If we have any hope of processing gigs and gigs of data then we need to take time to make sure we're doing so as efficiently as possible.
2. The core of algorithms hasn't changed, but I think what programmers need these days has. I think more programmers need the formerly "specialized"/"advanced" techniques these days.
Your post made me start thinking of whether my book would be any different had I written it ten years ago. Maybe segment trees wouldn't have been in there. And the challenge level of problems may have been lower -- we keep pushing the envelope on the problems we solve, that's for sure!
Thank you,
Dan