Attributes are fundamentally a lot of "sacred cows" that kind of are "iconic" to D&D that... kind of have to be tackled.
Why are the ability scores even what they are?
Well, naturally because holy be his name, the one and only truth, savior and law bringer from upon high Lord Gary Gygax named these and these alone to be the virtues upon which a character shall be defined.....
Or, you know, one Tolkien/Wargaming geek who was literally wargaming in his basement with his buddies decided 'hey, wouldn't it be cool if instead of army vs. army, this was more about a small group of heroes on adventures where they fought through groups of monsters just like the Hobbit and the first book of Lord of the Rings? Let me try to tackle this..." and well... those just happened to be the first set of traits on which to define a character that popped into his mind.
And there is plenty to criticize about it. For instance, is it really sensible that one's ability to move their body quickly to get out of the way of blades, arrows and traps should also be intrinsically linked to one's hand-eye coordination and steadiness of one's hands when firing a bow? And isn't one's physical raw muscle power so inherently linked to one's ability to withstand physical abuse to the point where virtually any character who is strong is going to be tough and visa-versa? So why are those different traits? And the division between Wisdom and Intelligence has always been questionable at best. The two words are synonyms and even later editions more clearly tried to make clearer divisions between them, there really should be a better word for "Wisdom" like... "Spirit" or something. No other use of the term "Wisdom" means "willpower and awareness as OPPOSED to acquired knowledge"
The fact that the game is required to use these 6 attributes and only these 6 attributes when defining class abilities has been a serious game hurdle with every edition. Particularly given that when creating a character we are expected to treat these attributes equally-- whether when rolling for them or buying them-- even though years of having played these games with this list have indicated that the 6 scores are absolutely not created equally and in fact there are a couple that virtually every character needs to have a decent number in so as to survive while others are complete trash that are not at all relevant to your experience playing the game unless you are playing one particular class.
And then there is the problem of them being measured 1-20, or generally, 3-18. The only reason we have this scale at all is so that they could be determined on a roll of 3d6-- for the simple reasons that d6s are the most common die type and rolling 3 of them gave a much greater chance for a fairly average score than if you were rolling only a single die in which the extremes would be far more common. This made it so that one would create a fairly average member of the society.
Hell-- originally, the Gygaxian model was to even roll the 6 attributes in order from top to bottom and that was what you were stuck with. Good luck choosing your class from there-- you were lucky to be qualified to be anything but a Warrior, which was the default class that you automatically qualified for even if you had only 3s across the board.
This was dissatisfying for two reasons-- first, it prevented players from playing what they wanted to play, which basically created a situation where players were being told to commit dozens of hours taking on the roll of a thoughtless, randomly created average slub that wasn't at all from their own personal inspirations... and, pretty lore breaking if anyone had ever given it much thought, the general set-up of D&D games don't make any sense at all that one is a totally untalented person literally torn randomly from the general populace. The idea that it was these people who might very well have no above-average qualities at all, who might even have some serious detrimental traits that would hamper their likely survival outside a menial job, who were the ones taking up this life of being an "adventurer" really stretched beyond all credibility. No current military actively recruits anyone who would be the equivalent of a D&D character with any score below 8 and very much require that one's physical stats are at least 13 across the board-- even if their actual role in the organization is support based. Adventurers in the D&D world would even more so be the elite of their particular communities. One is not going to be taking up mercenary work if they are crippled, sickly, entirely repugnant, woefully gullible or dumb as a rock. Unless the adventure was very clearly set up that your characters really were somehow very random nobodies who were caught up in all this through a stroke of very bad luck, character creation made no sense.
And if your characters were nobodies who were caught up in madness, you know what would happen? After just some time engaging in physical activity, your strength and toughness and endurance would increase, the more you practiced engaging in battle and dodging things headed your way, the better you would get at it, as you have more adventures and find out more about the world your knowledge would increase, as you faced dangers no one else had then your boldness would increase, and as you had more adventures and met more people and had more reason to have confidence in yourself as well as some measure of fame, your social skills would no doubt improve....
But in the original system, attributes never increased.... not without the use of magical items. Somehow the game presumed that the characters were as strong and swift and tough and clever and knowledgeable and charming as they ever could possibly be without the intervention of magic and it was solely their battle abilities that could ever improve.
Not that the later editions of D&D where you could increase your scores over time ever got this right. The thing about it is that they treat all attribute increased equally. But, if you really think about it... someone who is far stronger than the average but quite dim should find that more active engagement with the world is going to cause them to become far more clever than they originally were faster than they could be expected to develop super human strength.... and, similarly, the physically weak valedictorian who finds themselves traversing dungeons is going to naturally become far more athletic than they were when constantly hitting the books far more easily than gaining a masters degree level intellect simply because they have been blasting people with flames launched from their hand...
What I am trying to get at is, unless a person is somehow disabled, one should find it far easier to increase one's most lacking aspects over the course of adventuring which places many general and varied challenges upon them than to increase in the specialty their previous lifestyle and specialized training caused them to excel in.
The other ability touched on by the OP here is well... going back to how these were determined on a scale from 3-18 based on what die were being rolled for determining them. Well, semi-originally these scores had a number of confusing bonuses which each ran across different gradated scales. This meant an increase of 1 point in most cases granted you some sort of bonus. But, again, there seemed to be little rhyme or reason to how much or little the myriad of bonuses associated with each score increased. 3rd edition simplified this by each number in a score granting a particular numerical bonus to all abilities associated with the score and that same number giving the same numerical bonus for each score. A 12 was always a +1 regardless of what attribute it was associated with. But the numbers were still determined on a scale from 3 to 18-- which created a problem which was apparent even back then, odd numbers grant the same bonus as the even number one less than them. There was no longer any meaning to increasing a score by 1 point unless you were going from an odd number to an even one. And yet the game still contained various methods through which one could and would receive an odd numbered bonus to an attribute score which would be the one scenario in which they stopped being meaningless. And that situation persists to even this day even though basically no one determines their attributes by rolling 3d6s and those odd attribute adjustments past character creation have become far more rare...
Basically what I am getting at is
* The actual attributes implemented in the game is totally arbitrary and even after 5 editions a really crap job has been done of making them equally valuable even though the same "price tag" is slapped on all 6 as though they were.
* The way attributes affect the game and the way they are increased make no sense.
* The stats being measured 1-20 is based on reasons that are no longer valid in the game and hamper it.
Now, the general idea of attribute score increases being based on point buy instead of flat bonuses? I like it!! In fact, I feel like this should be the way that racial attribute adjustments also worked. So choosing the Elf race after determining a Dexterity of score 8 should maybe increase your score to 12 while if you already have a 16 in your Dex stat, maybe it only increases you to 17.
The only thing I don't like is this concept of "half feats". While there are some feats that can be neatly divided, I don't think that all can be and I feel like that is going to be an issue when implementing this.
