I've seen a lot of suggestions for different varieties of docking ports, but none of them mention the main issue I have with the little devils. That being the fact that any craft with multiple modules has a really hard time with acceleration. This makes it hard to build and operate crafts which are designed to be launched in multiple phases, docked in orbit, then flown elsewhere, or even Apollo style craft which launch on a single ascent stage then separate and dock in orbit. Any time I attempt such a project, I'm always defeated by my docking ports. The modules just want to separate whenever there's any significant amount of acceleration. It doesn't have to be a super large craft either. For example, my latest attempt at this sort of concept was an Apollo style craft that included a small and very simple lander module consisting of a single command pod, small fuel tank, engine, and legs, with a docking port position at the top of the command pod. The other module was a deep space tug, consisting of sizable tanks of hydrolox and an engine, with a docking port on top. The goal of the mission was to carry the lander into orbit of a moon of Todos using the tug, separate, land, then return to dock with the tug and travel back home. Super simple design, and it should have worked flawlessly, but I couldn't get out of droo orbit without the lander detaching and being left behind by the tug.
