Brake experts..Some help needed on my 190e brakes

[Meza]

The car is a 93 2.6L 190E.
I have done over 50 brake jobs on many cars. My wife drives the car and I hardly drive it. Until I drove it to Charleston, SC over a weekend and the damn thing would not stop like it should and make a sound as if the pads are almost down to the metal. I got home and ordered new Balo disks and OEM MB pads front and back. The next weeked I changed all the disks and pads and flushed the fluid with new DOT4. The old front pads had a bout 1 cm left and the rear are as good as new. I took the car for a test drive to seat the pads and it just doesn't feel right. It stops good, however, I feel like there is a delay before they respond and the pedal travels more. I called a friend and re-bled the brake lines again. No improvement. I think now that I need a master cylinder, but it's not leaking externally. All calipers move freely and pulling. Is the ABS has anything to do with this low pedal/delay brake feel or is it the master cylinder. It's about $200 and don't really want to replace it if not need. I just want to know if there's anything I am missing before replacing it!
Any help would be appreciated..
Meza