will reversible transactions complicate the system, make it less secure and stable?
Reversible transactions cannot be possible in decentralization.
Who will take care of disputes and be in charge of reversing transaction? In P2P environment, transacting in low volume and then transacting through escrow are the solution which eliminates the need of reversible transaction. Do we have that with fiats? Yeah, having but possible only through lawsuit. Same applies here on bitcoin transactions as well.