I will try to get into the game mechanics a little bit more than the other answers, showing you what those values really mean in D&D 4e.
We need something to compare these values to so I'll use a small subset of the possible point-buy arrays, the ones that grant us the best tactical advantage:
- The unbalanced array, 18 14 11 10 10 8, very useful for strikers and characters who prioritize hitting above high defenses.
- The balanced array, 16 16 12 12 10 8, or the very similar 16 16 13 11 10 8, useful for all other builds
Some other combinations are possible, but they get only used in special cases where characters need at least a 13 in four different stats, because of feat requirements.
While the rolled character can't ever compete with the unbalanced array (which is the favourite of many strikers), I will include it for comparison.
All six abilities contribute to at least one skill. But having a +1 or a +2 in a wider array of skills is not game-unbalancing.
This character is gonna get a +4 after racial modifiers at best, which is in line with the balanced array. Supposing the balanced array gets used at its best, with 16s matching the racial +2s, this means he will get a +3 instead of a +4 in some skills and a character-wide +1 boost on all others. Very not game-breaking.
He's way better than the unbalanced array but you see, that array is not even looking at its skills. It only cares for hitting figures.
Three different abilities are used to calculate defenses. Sometimes a class feature moves the AC-determining stat around, but you still need a third ability to keep reflexes up.
Hence, we're looking at the three better stats only.
- Unbalanced: +4 +2 +0 or
- Balanced: +3 +3 +1
- His: +3 +2 +2
As you can see, he someway covers his weak point. After racials (and supposing racial bonuses don't both cover the same defense) we have:
- +5 +3 +0 or +5 +2 +1 for defense-wary strikers.
- +4 +4 +1
- +4 +3 +2
...which means he still has some weakness.
Now, your powers usually ask you to raise two stats that contribute to the same defense.
This means your second best value is not available for defenses, and we get these figures:
- +5 +0 +0
- +4 +1 +1
- +4 +2 +2
As you can see in this case the rolled character fares better, totalling a net +1 increase on both weak defenses.
Calculations for human characters are a little bit different and we'd need to factor in the +1 to all non-AC defenses (very useful to unbalanced array characters).
So your array characters have a weak point, a low defense that is destined to become wider and wider in time as most builds go glass cannon and stack all their ability bonuses in the same two abilities.
This character has a slightly more protected weak point, at the cost of slightly less protected other defenses. This of course is advantageous to him, but not that much.
Now, if the other players rolled at least two 16s they're not running behind the expected figures, but a single 16 is often enough to get a decent character, because riders (the effects based on a secondary ability) can be ignored for a good number of builds.