I think #7, as I said before but I'll actually explain this time
Over 20 @ 18 encourages overly defensive play, which RELIES on the mass amounts of life rep instead of dueling strategies.
Over 30 at tvt encourages overly defensive play which results in your 2 50 rep chars running around each other at the end of the duel doing fuck all to each other.

I think a class by class or build by build cap is more appropriate because by lowering the rep cap across classes you might actually make underdog builds even less powerful.

The intent of a class by class or build by build cap would narrow the gap more effectively imo but there would need to be a lot of testing involved to determine appropriate ballpark ranges.

Also what needs to be considered is that the higher the life rep cap, usually the more defensive the duels become

I am 100% agreed with this.
Fake edit: are you photobuckets still down so we can make paint fun of you?

does any class need a cap other than fissure?

it works i think i had a 4 hour ban from my IT department.

fuuuuuuuu there goes my fun for the night.

this is the only class i can think of that can exploit p skulls and still kill effectively.
that is why i ddint think it was a problem to have 50rep on a 18 cb sorc but that is just my useless opinion.

wof sins

which are the equivalent of a low damage stunning fissure dudu, which cost alot more mana to do a relatively equal amount of damage.

I couuld get 39 on my necro and with a 1/10rep/2os circlet I could get 51.

I would only lose 1 frame of fcr.

So I do think it needs to be limited across the board. Some characters NEED to play defensively though, since their damage is low and they have to chip away at their opponents to win.