I think they were useless in 3e because they were too small, but now they are fine. Even +2 is a help, since it gives you an edge against non-rogue foes, if you have +4 or more it is very useful.
What's more, there is nothing to prevent rangers from occasionally spending cross-class skill points to get a rank or two in bluff or sense motive.
The only problem I've come across with them is DM-based, since the bonus can be a meta-gamey in identification of something "Spot check 14, or 20 if it is human". "you spot it because it makes typically human attempts to hide". That might not be a bad thing though.
Cheers,