Actually, all the US light tanks did rather badly in the Pacific. The M2 and M3 lights were found to be well, too light. They regularly impalled themselves on Palm stumps during the Island campaigns in US Marine service. In Australian service, they would found not to have sufficient "oomph" to get out of the swamps they often found themselves in (they were quite able to bog themselves). The Matilda was an excellent vehicle and was substituted for the US lights in Australian service. It had sufficient armour to withstand most Japanese AT weapons and sufficient power to get out of the swamps it often found itself in. The US Marines substituted the M4. The Australians, after trials opted for the Churchill, buying over 200 of them but they didn't arrive before the war ended. Churchill Mk VII was found to have better soft ground performance and wide enough tracks to cross most difficult ground. The M4 was basically a failure as far as the Australians were concerned. It's armour was too thin and it was underpowered.Depends on what you want the tank to do.
There's a place for Scouting and Exploitation, where speed and smaller size is a bonus.
But small and light rules out many of the other things on that list.
But all should note, that the M3 Stuarts did well as 'Infantry Tanks' in the Pacific, given to poor distribution of Armor and AT Guns in the Japanese Army.
Besides the unnatural addictions to machine guns everywhere, the M3 had Radio, and peashooter 37mm had a very useful anti-personnel canister round.
About the only thing it couldn't do, was toss smoke, and lacked the telephone on the rear to talk with infantry
So a proper small US Infantry Tank early in the war, could have been an up armored M3 with an M8 75mm pack howitzer, with a proper top and TC cupola