I'm a little wary about the "skills are just situational bonuses" thing. There's a possibility of things like (exaggerating for effect) "+2 to Intelligence at night, under a gibbuous moon, when wearing purple, but not in front of someone to whom you are indebted, and only while the King of Gerunthy still reigns from the Throne of Skulls."
Too narrow and weird, right? And what if a bonus-seeking player munchkins the situation to max out their fiddly little bonuses? Or if they seek bonuses that hit a certain situation, or ability score?
This is probably a solvable problem, but it is something to watch out for. It would be really easy under this system to grant bonuses that are too fiddly, or too broad, or easily exploitable. The burden on the DM to keep these in line would be pretty great.
Well, my homebrewed system uses something very like this. Basically, you choose a "secondary skill" for your character that describes what you did before you became an adventurer (or what you do alongside adventuring). You might choose blacksmith, farmer, weaver, sculptor, diplomat, historian, messenger, cartographer, thief, goldsmith, priest or whatever- it's your old job.
Now, let's say the dm calls for a Charisma check as you navigate through a halfling shanty town. If the dm agrees that your secondary system applies directly, you get a +3 bonus to your ability score when you make your check; if it applies indirectly, you get a +2 bonus. So if your secondary skill was thief or messenger, you might ask the dm if you get +3 ("Sure," I would reply if I were the dm); OTOH the dm might say, "Well, messengers only come to this area rarely- you only get +2." (Or he might deny you outright, if you were a diplomat or goldsmith.)
In practice, this is very easy to adjudicate, and as long as you give the pcs the choice of what the skill is, subject to dm approval, they probably won't get screwed by it.
Re: All the people worried about rolling stats- point buy will be there as an option. Just use it. Rolling has always been either the primary, or at the very least a primary, means of stat generation by RAW; in practice, many groups prefer point buy, but that certainly isn't every group. (I'll never allow point buy in my campaign, for instance.)