There are good arguments for big chambers as well, so we need to consider both sides. Cooling of bigger chamber is easier, as we have the law of cubes-squares (

There are good arguments for big chambers as well, so we need to consider both sides. Cooling of bigger chamber is easier, as we have the law of cubes-squares (volume growth against area growth with growth of the size). We have less parts, so less things to fail. Also potentially better mass efficiency (thrust to mass), as some elements can't be scaled proportionally to smaller sizes. For big rockets, where such chambers would be appropriate, we don't need particularly fast control system. Saturn-V could even be flown with manual control, and astronauts were trained to do that. Of course there are advantages with smaller chambers and smaller engines too.