Unfortunately, needing that amount of render delay is very uncommon, and there is little chance that we will be increasing the default limit. If you are getting a 1.5s delay on a USB3-based capture device, there is something very wrong with either your PC or the capture device, and you should look in to correcting that instead. If you are still using a USB2 capture device, my recommendation would be to upgrade to a newer device if the current workarounds are not acceptable to you anymore.