This is an interesting idea. You would have to have a large selection of potential skills, so that you get access to new ones fairly often, and it would have to balance so the skills aquired at the end of hte game would still be as useful as the ridiculously high leveled ones that you've been leveling up all game.

I 100% agree with the system. I have a very similar system in my DD, though it's very balanced.

Make sure the system doesn't go just one way. Put level caps for certain levels that keep players from doing super specialization. For instance if you have a list of stats like
social
physical
social

if a player is level 1 and levels up make it so the max stat amount for the stats are like 5 or something. If a person is given 10 points it makes them distribute them and not just be like they have to use all their points in one category to get the uber last skill.

Also you hit one of the key ideas, linked stats. Having 1 social and 5 physical could open up a make threat skill. Also if you plan on high levels of skills reserve high levels for added equipment or other RPG stuff.

like if a max for the physical stat is 100, set the max a player can add to it around 70, then certain equipment would keep adding up to unlock special 1337 abilities.

For instance you said hacker. A person might have a level 70 hacker ability and have a hacking device with increases the stat +8 unlocking a new ability that wasn't available previously.

There's tons of systems. A feat system or passive ability tree is usually combined along with a stat system like yours. Meaning that a hierarchy of passive skills are available. Like at level 5 a player could unlock level 1 hacking allowing them to use a new hacking devices and a +1 to hacking.

I think you get the idea.