I'd post some paintings but this sub doesn't allow it. Many paintings from the 15th century depict people wearing colorful leggings which are essentially a baseline for my two questions, which are:
Why did people no longer wear longer gambesons like in the earlier centuries to protect their thighs? All of the paintings depict people either wearing leg armor or just those leggings without any protection. Was it because of fashion?
The second question regards shoes. In many paintings there are two things depicted at the same time. One being people wearing those leggings and shoes (which is what one would expect) and other being people not wearing any shoes and having those leggings covering their feet as well as legs. Was it a thing that people in this century just walked around in their leggings that also covered their feet? So essentially without shoes and just with some cloth on their feet?
(Sorry if the wording is weird, english isn't my native language and I struggle with explaining things)
First, if by "men at arms" you mean gendarmes, those would be heavy armored cavalry.
But if you mean foot soldiers, like the Swiss halberdiers, English pikemen or German Landsknechten, by the later 15th c. their tactics would require fast movement, and being lightly armored, their legs unencumbered, helped them move quickly. Pikes and polearms were also most effective at maximum impact, and so a body of pikemen would charge fast. If that first impact failed, there was always a risk that the two sides would become locked together in "the push of the pike" and pikes would no longer be very effective. It would then become a contest to see which side could push the other side to break. In the process of that push, many soldiers would be killed, many simply by being crushed.