Help with diag on a VW brake issue

As it's been a good 15 years since I've been motorsporting, I keep thinking more and more about jumping back in.

I currently have this 2013 Jetta with the 2.5, 145K on the clock.  I'm on the fence about buying something cheap just to thrash or to run this car.  I would plan on running 16's with 225/50 200 TW tires.

The issue I've had since I got the car is the brakes arent great.  I have bled them once already.  In a panic stop situation the pedal is kinda soft and the car feels like it wants to pull, but generally stays straight.  Also, at a stop on flat ground, I can slowly push the pedal to the floor.   If the hill holder thing is active the pedal is hard as a rock and wont go to the floor.   Pumping the brakes on a flat doesnt seem to make any difference. would this lead straight to the master?  Is the fact that that the car has a vacuum pump just making the pedal way over boosted? It's a fairly common mod to remove them with this engine, although mostly due to oil leaks.  Or is the master just bad?  Could it be a old or sticky caliper? 

I've heard braded lines over the stock rubber will help pedal feel a bit and plan on installing those if I can figure out the main issue.

Are you losing any fluid?  The fact that you can eventually push the pedal to the floor is concerning.

How long does this take? Length of a red-light, maybe less? What happens after that? Does the car eventually start to creep forward/can you overcome the brakes by giving it gas (if its an auto)?

For what it's worth, I'm having the same exact issue in my wife's 09 Sportwagen.  Brakes were fine, then I replaced all the calipers, pads, rotos, flex hoses, parking brake cables. I suspect the master cyl went dry at some point during the job and air got into the abs system, but I'm having a hell of a time bleeding it out.  I've tried using the vagcom to activate the ABS pump, but still haven't gotten a good pedal.

The pedal is firm with the car is off, but the bite is really low when it's running - and creeps down but doesn't hit the floor.  Car still stops fine, but it isn't confidence inspiring vs my GTI that has a higher, firmer pedal.

To be absolutely sure, I'm replacing the master at the end of this week (bench bleeding it first...), then rinse-repeat the bleed process.

I'd start with bleeding the brakes with you activate the ABS pump.