More or less yeah. People should expect 4-5 years out of any machine built these days, even higher quality laptops. AMDs gains seem greater than they are because their chips were garbage for so long. We're approaching the limits of silicon and I don't expect anything miraculous without a fundamentally different manufacturing process.
Totally depends on your usage. If you're regretting not having more cores like I was when I upgraded from my 2500k then you could get basically anything. If you're looking for more gaming oomph, then you're going to be waiting for a while.