Literally the entire purpose of scripts is to create and manipulate variables, such as attributes, that affect the character and game surroundings. There is no doubt that this will be possible, unless BGS decides not to release the Creation Kit. Creating and integrating an attribute system throughout every aspect of the game will probably be a huge and non-trivial task, though.
That's pretty much my reaction too, and seems to be something close to the consensus of the thread. Fitting attributes into the game shouldn't be that difficult (with the proviso that I do understand the sort of work that goes into scripting, so that "not that difficult" is a relative measure rather than a simple descriptor), but balancing them in the game would be another order of complexity entirely. The game will certainly be set up to dole out and keep track of bonuses and penalties, so it should be relatively straightforward to hook into that system and dole them out at other times and/or for other reasons. But if the game is set up (as promised) to dole out a balanced amount of bonuses/penalties based solely on perks, then the inclusion of attributes would have to be as a part of the source of those bonuses/penalties, rather than in addition to them.
I woud think the simplest way to do it would be to make them roughly fixed from the beginning. I know this flies in the face of Beth's stated goals for the game, but Beth's stated goals for the game fly in the face of the way that many people prefer to play. If I create a Nord warrior who's strong and tough and quite literally dumb as a post (Hale started with 65 strength and endurance, from race, birthsign and preferred attribute bonuses, then I consoled his intelligence down to 10), then that's because I want to play a Nord who's strong and tough and dumb as a post. Access to attributes, even only at character creation, would add to the roleplay, and if it was only set at character creation, then it could be balanced with the rest of the perks right from the start. Script it so that an increase of X% to an attribute entails a decrease of X% of the gain from any perks that correspond with that attribute. Once set for a particular character, it would never have to be adjusted. You'd still certainly run into balancing issues, but that would at least tend to minimize them. But it might hamstring the character more than even many of those who desire attributes would want. I'm okay with it, but I don't know how many players would be. But - if the attributes can change over time, then the mod would have to keep checking attributes and keep adjusting perks accordingly, which would add to both the overhead and the complexity of balancing it.
Just some musings..... I have little doubt that someone much more skilled than I am will go ahead and do it, one way or another.....