Broly just doesn't have the stats to equal his destructive power.
Not true, he literally was untouchable till the very end when the miracle punch came to play. PIS my friend.
Broly just doesn't have the stats to equal his destructive power. While they are good, the fact that he lost to characters significantly weaker than Janemba not once but twice shouldn't be ignored.
The way he lost both times were so ridiculous it isn't even funny. Like really man, a ghost Goku in the second film and energy from half dead Saiyans in the first one. If anything those scenarios shouldn't be ignored.
His durability is not so high that characters of Janemba's caliber cannot harm him and speed-wise he isn't good enough either.
His durability was far more than that of an SSJ2 to scratch him, it doesn't matter if Gohan was weaker or not he is still way above an FPSSJ. Speed-wise/reaction-wise, in the first film all of them were attacking and he dodged every punch and kick. Also in the second he blitzed the crap out of an SSJ2 Gohan. Those are noticeable feats for someone people see as only a tank.
Ssj3 Goku who not only is faster in attack speed but had Shunkan Ido (also it was halo ssj3) still was overwhelmed by Janemba.
Tbh, it looked like Goku was doing a half decent job until the sword came out.
Broly can't beat Broly and Janemba even if he could manage Janemba alone. The same for the rest although only Majin Buu is worth a mention out of the 3 of them.
Debatable, I don't see his own attacks hurting him as much here, even a casual blast from Broly is more than these guys can take. Especially with the insults flying around, Janemba should be significantly weakened enough to get blasted.