They need to do a lot of things this Off-season. Klay Thompson himself won't make them Contenders instantly. Klay won't be as great of a defender as he is back then. Offensively he would still be good. But defensively he's not an All-Defensive type player anymore. So my opinion on what they should add this Off-season is, DEFENSE.
Trades
Warriors add: Kawhi Leonard, Myles Turner and Derrick Rose(FA)
Warriors lose: Andrew Wiggins, Kelly Oubre Jr., Eric Paschall, Kent Bazemore, Mychal Mulder, 2023 1st round pick, 2026 1st round pick, 2022 2nd round pick (via Toronto) and 2022 2nd round pick.
Explanation:
As I said they need DEFENSE. They add 2 All-Defensive type talent on the roster in Kawhi Leonard (who has just been name an All-Defensive 2nd team player) and Myles Turner (who probably made it if he didn't get Injured). Those 2 players are also good offensive players. Both players are good 3-level-scorer.
Draft
Select Scottie Barnes with the 6th overall pick.
Select Moses Moody or Franz Wagner with the 14th overall pick.
Explanation:
Scottie Barnes is the best defender in the draft and for me its not that close. He's also a great playmaker and an explosive player. (Comparison: Draymond Green) Draymond is already in the roster. And imagine having a guy off the bench who plays like your starter? That's a W.
Moses Moody he's only 18 years old. Has a lot of potential. He's also a great (or good) 3&D guy.
Franz Wagner also a great (or good) 3&D guy. Versatile defender who can guard multiple positions.
Roster:
Starting 5:
PG: Stephen Curry
SG: Klay Thompson
SF: Kawhi Leonard
PF: Draymond Green
C: Myles Turner
Bench:
PG: D.Rose
SG: J.Poole | D.Lee
SF: M.Moody or F.Wagner | JTA
PF: S.Barnes | A.Smailagic
C: J.Wiseman | K.Looney