Perfect? That's very nice of you.D&D is perfect for dungeon-crawling, but not so good for other games with more investigation or social interactions.
Hmm. Optional attributes? I'm not sure if this has been done (Fate's aspects), is actually a skill idea instead of attributes, or if it is worth fleshing out.Other idea is some attributes are modular, optional, this means you are free if you want to use them in your game or not. Maybe in a sci-fi game only one PC has Techniche attribute because she is a techy who repairs/fixes machines, or a cofrater (member of a brotherhood, a jedi knight ersatz) with martial maneuvers of light saber. Maybe a DM would rather to use Technique because she wants (munchkin) players to choose between better Agility for Reflex saves or better technique for stealth or to disarm traps, martial maneuvers or drawing runes.
I'm interpreting your example to mean breaking up Dexterity into two attributes, and spreading the related rules around. That strikes me as top-down engineering of D&D's (thoroughly playtested) rules, which is risky, but also probably where the term "house rule" first came up. Go right ahead, but I wouldn't expect all of the third-party publishers to jump on the bandwagon.
INT is for nerds? I don't know if this will scare away or draw more PCs to it.* My own point of view see the differences between Inteligent, Wisdow and Acuity, but maybe others can't. Int is the nerd who goes to the university thanks a scolarship or the chess game champion. . .
You're redesigning attributes, right? If I were you, I'd try to make all attributes useful.* To avoid some abuse by munchkins I have thought about two pools of creation points, one for the main abilities scores, and the other for the attributes no-so-useful.