This is 3 in 1 suggestion so I'll keep it short.
The suicide vest atm seems too easy to pick up and use and it'd be nice to make it so people consider the tool's downs and ups before they pick it and even use it in battle.
- Make it so only the assault class can equip it.
- When you have used it (blown yourself up and killed 2-5 enemies or whatever) you can't be revived and you must return to the spawn selection screen.
- Slight AoE buff (edited in bullet point)
This'll easily make the C4 vest less spamy or be seen as a meme tool and actually force the player to consider the right type of situations to use it.