I did not quote a TPS estimate for TF but an estimate of it's DPS factoring the Proc on top of it's base 53.9dps
Literally just to give you an impression of the DPS of the weapon expressing the proc as part of it's DPS.
At around 6ppm for 300 damage a time that's +30dps hence you can view TF as an ~83.9dps weapon (people usually quote 80-90dps but this is how I get my figure).
People did massive test of TF's proc rate and came up with ever decreasing figures (one of the the first owner claimed it was >30% but by the time people had done many thousands of swings the estimates were down to 17-19%).
Stance / Threat modifiers are the same for everyone assuming Defence/Defiance.
If you wanted to see the true threat difference then use the Spreadsheet with the Brutalizer vs TFs stats (i.e. 1.9 speed, 53.9dps, no Expertise, some Agility) and manually add on the Threat from 6ppm of the Thunderfury Effect Proc yourself - at the end.
I make this:
270 x 1.495 = 403.65 Threat per Proc.
At 6ppm that's 2421.9 TPM
40.365 TPS
What I can't remember is the innate Threat from the Thunderfury Resistance Debuff - I used to be about 200 but they nerfed it to near insignificance.
I will run my theory through the TPS Spreadsheet myself and report back here shortly. Incidentally 2 weeks ago I did a KZ clear and started out with TF for "fun" but went back to my Brutalizer when I consistantly felt I was underperforming or even more rage-starved due to lack of white damage.
I am happy to do a more empirical test with Omen
OK here's my results from the Threatdown 4.1 Spreadsheet:
Using The Brutalizer it estimates 1051.8 TPS
Changing only the stats relevant to a switch to TF I get 920.31 TPS
That's a deficit of 131.49 TPS to make up with the TF Proc. My conservative estimate that the TF Proc gives another 40.365 TPS leaves > 90 TPS gap. I doubt the most optimistic calculation of TF threat can close that gap.