Dragon Claw
Essentially, Dragon Claw is the strongest defensive item when facing teams with a lot of magic damage. However, this item has many weaknesses that deter players from using it. This item only increases the defense of the unit that possesses it, but strong magic damage compositions can deal significant area damage. Clearly, when the entire team is taken down, a single unit holding a Dragon Claw cannot win.

Furthermore, Dragon Claw does not provide any additional effects other than reducing magic damage. Therefore, players often overlook this item for Thornmail for their tank champions as it has the ability to reduce critical damage. Even for carry positions, defensive items like Quicksilver, Trap Claw, and Guardian Angel are more useful than Dragon Claw. Perhaps Riot should add some effect to Dragon Claw, such as healing based on the damage reduced, to make this item less “useless.”
Bloodthirster
The problem with Bloodthirster is similar to that of Dragon Claw, as this item only provides a single effect for the champion that possesses it, which is lifesteal. Remember that with the current meta revolving around carries that deal too much damage, your units will be eliminated very quickly and have no time to lifesteal. Therefore, players tend to build items that can burst damage for physical carries like Infinity Edge or Giant Slayer instead of Bloodthirster.

Additionally, with the introduction of the Bloodsucker trait providing healing, Bloodthirster is even less frequently used. Why would you want to take up a slot in your carry’s inventory when you can get free healing from the Bloodsucker effect? To make Bloodthirster more useful, Riot Games should add damage-dealing effects to this item. At the very least, they should give it a shielding ability similar to what Hextech Gunblade currently has.
Frozen Heart
This item has a critical weakness, which is its limited range of effect, meaning it can only reduce the attack speed of melee champions. For frontline tank units, this is almost meaningless as their energy regeneration primarily comes from taking damage. Perhaps Frozen Heart can only counter the Duelist composition with many melee carries. Moreover, the practicality of Frozen Heart is extremely low.

Another reason why Frozen Heart is becoming increasingly “useless” is the overwhelming popularity of the Master trait. The Master trait can reduce the attack speed of the entire opposing team, regardless of distance, making it vastly superior to Frozen Heart. Making Frozen Heart more useful is a very challenging task. Perhaps we will have to wait until Teamfight Tactics season 4 ends and the Master trait no longer exists for this item to be used again.