Its not just capacity either, pedal feel and level of servo assistance are exceptionally poor, for my taste.
Having owned (in addition to company vehicles) a few samll/medium sized Fords, I prefer the Omega feel. I feel its more controllable.
But, agreed, after a week driving a shitbox focus, jumping in a 3.0l Omega with cold TC pads, there was an element of clench when approaching the carpark barrier 
Absolutely 
Drive ANY other car, the brakes have more assistance. Jump back in the omega, CHRIST!
, but the brain soon re calibrates when scared 
There are a few options that "look" like they might work. 18" wheels helps. Alot! 
Not sure I want my assistance to the brakes. Durability, maybe - you can never have enough brake durability
. That said, you have to drive pretty hard to get any brake problems. (Note, talking about road use - they wouldn't stand up to track)
One option

Probably wont fit in an oe 17" wheel.
Hit the nail on the head there - Omegas are an old car now, running 16" or latterly 17" wheels - on the V6s same dia brake disk though pre, minif/l and f/l. Most modern cars are generally runnng bigger wheels, allowing use of bigger discs, together with more modern style calipers, such as opposing pistons, twin and 4 pot.
Omega brakes suffering the limitations of age now.
Do agree though TC pads reasonably priced and adequate for normal road use.