Well, in my most humble opinion, the 75 isn't the best vehicle for hard launches from zero km/h. It has three issues (in stock form):
1) the stock clutch is too lightweight (moreso in the 2.0TS versions)
2) the donuts don't/won't last with repeated abuse
3) the 1st-2nd gear shift will instantly add 0.5 seconds to the best time possible
Having said that, the my 75 3.0V6 can and has suffered many hard launches. It's not bone-stock however. I have:
1) upgraded the clutch to a carbon-kevlar unit (USD 450.00)
2) added "donut protectors" to minimize the twisting of the rubber donuts; 2 years later with constant track abuse I haven't had to change donuts!
3) lightened the gears in the 'box; you still CANNOT slam-shift 1st-2nd (nor should you like most kids do in their Jap rice-rockets today) but it does improve shifting in all gears.
4) learned how to be nice to the driveline while also squeaking the most out of it. The only way to 'learn' this is when you have to change the darned donuts yourself in the dead of winter; you learn real fast!
What you're describing is quite normal, and the best way to get off the line on stock equipment is to let the clutch bite first (this takes up the slack in the driveline too), i.e. like Mats sez; launch below 3K rpm to get a good bite early. Then, roll on the throttle - don't stomp on it. You might lose half a fraction of a second, but unless the race is to 100km/h, the 75 will haul your behind once you're in 2nd gear and above.
Most would agree that the 75 does suck at stoplight derbys. My 'races' off-track will usually go between 100km/h to 220km/h, i.e. 3rd, 4th and 5th gear launches. The 75 does much better at those velocities.
Pick yer battles ....

or put it another way, pick the right tool for the job. I'd pick a cheapie Honda CRX with Nitrous if all I wanted to do was 0-100km/h.