Yes, the Sparring Gloves might be just a bit unbalanced — the main issue being that some combined items are overpowered compared to others. Don't worry, Riot is working on that!
Item Balance Changes
Deatblade
• Starts with 0 stacks → Starts with 1 stack (+15 AD)
Infinity Edge
• 150% Crit Damage → 125% Crit Damage
Quicksilver
• 5s cooldown → 3s cooldown
Thief's Gloves
• Lowered the average quality of item combinations
Sparring Gloves Changes
Riot Mort explained in one his last tweet the actual changes brought to the Thief's Gloves.
Chances to get a Tier X item according to the Player Level
Item Tier List
In this week 'Ask Riot', developers talk about the League of Legends Worlds meta, the experience gain in Teamfight Tactics, and the items that you can purchase thanks to Worlds tokens.