Blau, as you are finding in this and another of your threads, Frank is full of one liners that don't offer any information.

I've never been too impressed with the brake feel on my 97 SL320 and 97 C280. The SL has braking action as soon as you press the pedal however the response isn't linear making slow speed braking not so smooth. There is initial braking but pedal travel in the middle does little until you push farther then more braking suddenly occurs. This isn't a case of the brakes suddenly grabbing due to a lining issue.

Some master cylinders have a stepped bore and a quick take up valve, not sure if MB uses this or not. The quick take up larger bore is high volume / low pressure to get the calipers pistons against the pads and the smaller bore is low volume / high pressure to provide braking action.

If the transition is too early modulation is difficult and the pedal will be long. The human foot reacts much better to more / less pressure on the brake pedal than it does to more / less travel. Ideally, the brake pedal will not move at all and just react to force but this isn't possible with a regular system.

The C280 has an annoying initial high pedal force for the first 1/2" of travel then normal after that. This also makes it difficult to modulate the brakes because you are braking through a spring "hump".

If you have bled the brakes and had no improvement, another thing to throw into the mix is the ABS unit might have some air hiding in it. I'm wondering if using a scan tool to operate the ABS or a few hard stops to get it working would do the trick.

My 99 Ford Ranger has brakes that are great to modulate, the feel rivals the hydra boost unit on my 1980 Chevy 1 ton truck. ( the hydra boost unit is as close to a zero travel as you can get with a standard master cylinder. )