My son-in-law has just bought a Brompton, so I was able to compare (while static) his new brakes with my previous-generation ones. There's no doubt that his had the better feel - much firmer,although mine seem quite adequate. I've seen suggestions that replacing the blocks with third-party ones is the best upgrade?
I've also seen people talk about third-party brakes, the issue being that Bromptons feed their cables from below instead of from above. In the days of Weinmann brakes, of course, you just unbolted the fittings from the caliper, and swapped them, but I suppose that those days have gone.