Not really sure on first year. based on launch though I would easily give it to the PS2. PS1 and PS4 had pretty much nothing I wanted at launch. PS2 though had several games I craved. Games like International Superstar Soccer(later became PES), SSX, Tekken Tag tournament, Ready to Rumble 2.
PS2 most likely wins first year as well. Software like ...
Dead or Alive 2
Midnight Club
Unreal Tournament
King of fighters
PES
Knock out kings
PGA tour
Noe of Enders
Twisted Metal
Gran Turismo 3
Silent hill 2
Time Crysis 2
GTA 3
Devil May cry
Burnout
MGS 2
Baldur's Gate
and likely a crap ton of others I have forgotten. Compare that to PS4 and the PS2 likely has double the amount of software that really interested me.