You just said it yourself. Agility means :
- Steady hand (Security)
- Precise movement (Stealth)
- Falcon eye and balistics (marksman)
Are you really trying to say that if you are good at one of those, you are good at all of them? That if you improve one you improve all?
Yes half of abilities of character is relay on his natural attributes while another half on acquired skills thats is its natural modeling of an character, now they took out all natural properties of character and left only his acquired skills, if there will be no significant and detailed perk system thats will replace attributes in proper way, then half of player character representation in game become axed.
Since there is no anymore birthsigns, backgrounds, starting advantages and disadvantages, classes, we receive generic blank character at prison, I'm OK if such character will be optional as before we can create own class and such blank character can replace such option in some kind, but making generic blank character at prison as main choose without of any options looks really strange.
Attributes and classes was in TES from beginning of series, I don't think limited number of perks can properly replace fundamental basis, perk can work in conjuction with attributes and classes but not replace them completely until they are limited to 15 perks to one skill since they will add unique features mostly what have level trees, or number of perks will be increased really represent our character via starting traits-perks (birthsigns, advantages and disadvantages) predefined sets of perks (backgrounds, classes) and basis perks from nebulas what represent three main way of character development (The Mage, The Warrior, The Thief) what will included http://www.gamesas.com/index.php?/topic/1181187-perktributes/ (mix of perks and attributes have 100 level stages, rise automatically with leveling of skills from main tree and level of character have racial variability, but all levels are have visible changes on gameplay on certain stage for example at level 10 of Strength of Warrior perktribute tree character will receive bonus to weapon damage), such things as Perktributes can be done with mods,
but starting traits as birthsigns, advantages and disadvantages predefined sets of perks (backgrounds, classes) can be done by devs, there is nothing hard in such to such feature, not all like play as blank character, if they fear of casuals who will take wrong combination of race class and starting traits and then will cry at forums, make chose of starting traits available in hardcoe mod or be optional as before was class creator.