A higher V1 (engine failure speed) means a higher Accelerate-stop distance. V1 has to be above Vmcg. If you have a higher Vmcg, you need to mandatorily increase that V1 which means a higher Accelerate stop distance on a very short and slippery runway. A lower TO thrust means a lower Vmcg, means a lower V1, means more runway to stop, means a higher Take Off weight. Cheers.