As an "alien" living in the US I have to say that the Immigration officials do seem to be getting more human lately. I don't know if there has been a specific push to make the process less intimidating/painful, but I have flown into the US about 7 times this year and have had no trouble at all. Admittedly I have flown into Boston every time and that may be a particularly friendly airport - although you speak to Americans and New Englanders are supposedly the most unfriendly bunch of people around! In theory, ESTA should make their jobs easier and therefore they should be more friendly!
When I first moved over here 2.5 years ago, I was grilled every time I came into the country - who did I work for, where, how long, etc etc. Nowadays they are nowhere near as nosy