All things considered, to resume it all, my new list is like this:
1. D&D: the first. the one that started it all. Class system with level progression.
2. Gurps: Generic point buy system, classless.
3. Traveller: Career paths, nre atribute aprox. so many innovations.
4. Runequest: Skill system, D100, cults tied to magic.
5. CoC: Sanity rules. Investigation adventure approach, and, of course, mythos!
6. Ghostbusters: First ever dice pool game, metacurrency.
7. Vampire: New way of roleplay.
8. Ars Magica: Versatile magic, troupe stype.
9. Pendragon: Precursor for structure of the play loops, personality traits
10. Sorcerer: first in the indie games era and a new approach in the way of RPG design thinking tied to the players goals.
11. Fate: It came after Fudge (the original system) but it implemented the aspects systems that many games took after it.
12. Apocalypse World: Power by the Apocalypse. 'nough said!
13. D&D 3rd ed.: Introduced the SDR concept that allowed the OSR.
14. Castle and crusades: First hit in the OSR movement.
15. D&D 5th ed: Not the first, but Roll with Advantage/Disadvantage spreading. RPG popularity boost.
16. Mork Borg. OSR next level.
Honorable mentions:
Champions
Dogs in the Vineyard
Into the Odd
Mothership
Shadowdark