In past Elder Scrolls games, the bonuses you got to your attributes, the +1/3/5 bonus, were determined by how much you raised a skill related to that attribute.
Because of this however, by raising you major and minor skills, one would eventually reach a point where one would max out the attributes related to their major and minor skills long before they would finish leveling up because of the bonuses.
This ultimately made people have to level up attributes related to skills that weren't their major or minor skills, and by the time one was done leveling, one would have all their main attributes maxed, and most of the other attributes at very high level.
Since attributes in the Elder Scrolls, as with attributes in all other RPGs, control things like carry weight, stamina, magicka, health, and so on, the end result would be that most character would have similar, if not exactly the same stats.
The Warrior, Mage, and Thief characters that started off with wildly different levels of hp/magicka/stamina would all end up with basically the same levels in those things.
Past Elder Scrolls games leveling system could thus be described as a pyramid, the lower levels, or "base", were the most widespread and diverse your character ever got, but as you leveled up, or got close to the "tip" of the pyramid, the more similar they became.
By removing the major/minor skill system, and attributes, and replacing attributes with perks, Bethesda flipped the pyramid upside down.
Skyrim's leveling system is an upside down pyramid, everyone at the "base" is the same, however as they level up, and gain perks, they grow more varied from each other, getting more varied the close the reach the "top".
My Warrior, Mage, and Thief, who in this example have the same hp/magicka/stamina, and 100 in all skills, are VASTLY different from each other because of the perks they have.
-My warrior deals double damage and has special power attacks
-My thief can turn invisible when entering stealth
-My mage can cast uber-high level magic spells with almost zero magicka drain.
On the other hand my same characters in Oblivion, and Morrowind, with 100 in each attribute, and 100 in each skill, all deal the same damage with all weapons, get the same armor protection from all armors, and cast all the same spells for the same amount of magicka. The vast differences I started off with became negated.
It is the fundamental flaw of every RPG with an attribute system, from past Elder Scrolls games to Fallout.
A character with the same SPECIAL stats, in this example all 5s, and 100 in all skills, would be exactly the same as another character with all 5s in every SPECIAL and 100 in all skills, the perks in Fallout provide only menial differences between the two.
When you have things like Health/Magicka/Stamina/Action points/Carry Weight etc. etc. controlled by attributes it ends up making most character vastly similar.
I mean, in New Vegas, how many character really had a huge difference in carry weight? the answer. few.
Attribute systems impose conformity, and similarity, between characters, and unless you do some crazy min/max of attributes, like bringing your perception down to 1, the visible differences between having a 5 or 7 in said attribute are slim, to none.
Attribute systems have, and always will, impose conformity, and stifle character diversity, in RPGs by removing control of many important things that define your character out of your hands.