alright i read ur comment, pretty much all of what i said but more detailed..
LSSBroly is stronger than a ssj2. I put him roughly on par with fat buu - and then keeps growing stronger.
At SSJ broly took a kick to the neck and a large ki - blast to his unprotected back by a ultra ssj vegeta, without even noticing. Perfect cell flinched a little from a kick he saw comming.
Now take into account that Broly can get 50x(minimum) stronger than this.
I think your severely underestimating how impressive it is to walk away from a kamehamaha of that magnitude an not even be slightly scratched. I think it's pretty obvious that the power of it was enormous and also very concentrated, due to only the upper body being destroyed (presumably because goku thought that as long as the brain cells were destroyed, the fight was over). It shattered cell's upper body like glass and dispersed it. Broly, not only takes the full brunt of the damage unscathed, but he actually walks towards, without breaking stride, an extremely powerful attack. Cooler had to fly at high speed to pull of a similar manoeuvre.
Your forgetting that whilst the cell jr's could hurt the Z fighters, the Z fighters could also hurt them. Piccolo, trunks, vegeta even tien and yamcha.
However, A fresh piccolo and a rejuvenated goku (who consumed a senzu) weren't even effecting broly as they peppered him with strikes.
I agree with Akuma
It would take a ssj3 goku to finish off Broly. And as Akuma was saying, Broly was toying with them, he wanted to humiliate Kakarot and embarrass him, other wise he would have just killed him instantly and only attacked him. However, he also attacked everyone else for and threatened to kill gohan in front of him.
The aura lightning is not a valid reason.
Gotenks ssj3 fought super buu - no lightning
Goku ssj3 fought super buu - no lightning
Goku ssj2 fought Kid buu - no lightning
Goku transformed into a ssj3 - no lightning
Goku ssj3 fought Kid buu - no lightning
Vegeta SSJ 2 fought (.....) kid buu - no lightning.
Goku ssj3 fought hirudergarn - no lightning.
Goku has a lightning aura in his base form in the final episode
So based on that fact it's just as easy to say that not only did Broly fight evenly with a ssj2, he gained the upper hand, whilst in an extremely weakened condition.
However, even if your essay was correct, it would still be wrong. By pigeon holing Broly between Perfect Cell and SSJ 2 you have automatically given Broly the win. You yourself believe broly is much,much stronger than perfect cell, making him, logically marginally weaker than a ssj2. You would have to start off MUCH stronger than broly to defeat him as his power grows continuously. It wouldn't be long before he was gaining the upper hand against a ssj2. Goku or otherwise (assuming he was weaker - I don't think he is)
and the comment about when goku blasted broly with a kamehamaha at point blank range, broly even commented on it and said "what the hell was that suppose to be" , obviously that blast was S***.
and ur lightning statement, i might have to dissagree slightly...
during the SS3 transformation, goku did have lightning around him.
now while he's was fighting, there isnt any lighting i dont believe...but i could be wrong..
but i think the lightning is one of the ways to tell u if its an SS2 or not but only when the transformation happens or the power ups...i believe. other than that and hair change atleast for goku and gohan..i dont know what else..