The 2 triad unique roles are:
Double Flower and
49er

Double Flower is just plain OP, normally the only way to take out gov at day is with judge, but double flower just lets them take out gov for free. It's also kinda meh, after taking a shot DF has nothing to do but wait for DH to die.

49er is also kinda meh, like it's cool that it can prevent jailor and if u combo it with witch u can permanently disable someone but it's kinda low impact.

Why mafia is better:
Caporegime is super epic and can cause crazy comboes such as:
Kidnapper executing n1, kidnapper turning into disguiser, disguiser turning into another role, etc etc

Soldato is epic because it feels super impactful if played correctly, if you place it on gov you can blow up every prot role and LOs, it can outright win games.