Ok, just so I'm understanding the OP...
You are generalizing Invuln and WP effectiveness
regardless of whether they are a primary or secondary
power-set?
I have played the game since launch.
Took a break in 2009 until about 2 months ago.
My experience:
Invuln/SS > SS/Invuln starting from base
Assuming consistency (since I have not yet built a full WP build):
WP/SS > SS/WP starting from base
because your primary set gets dominance over your secondary set
and stats are adjusted accordingly
I built two nearly identical invuln builds (nearly because primary and secondary
sets are not identical pools)
One Invuln/SS Tanker the other SS/Invuln Brute, at lvl 24 with exact same
enh's maxed 3-4 slotted (where effective) and at x3 to level per slot SO's
which one do you think was tougher and could withstand normal random +2x2
mobs?
Running the same missions (I admit to using the DFB to PL each set to lvl 24 so I could
test each within a reasonable [before I got bored with the experiment] amount of time) my invuln Tanker not once face planted, while my Brute was becoming expert in floor inspection.
So back to my original question, how can you generalize comparisons overall for each build by using builds where the power-sets in the comparison are being used as secondaries and say that these figures apply to both brutes and tanks as a whole?