I had 2 porsches - I had a brand new '97 911 4S & a few year old 928 - both had great 1st gears. I also had the RX7, an Alfa, a Lotus, 3 Volvo's that were stick - none of them had this issue. My RX7 didn't have a great 1st gear but it didn't feel like you had to shift as soon as you started rolling. Maybe the 1st gear on the XF is just something you get used to after a while. Don't worry, I wouldn't kick it out of my garage for dripping oil......