Melee infantry are not at all useless - they have the best shields and the best melee skills. In perfect hybrid field armies they are the skirmish walls that prevent enemy cav from disrupting my ranged units.
They are a good forward line to lay out to soak up missiles, and nothing stands against them toe to toe 1 on 1.
Cav are more utilitarian, but one on one the elite infantry is going to have an edge over your elite cav.
if anything, this game is much more forgiving about ranged units because they carry secondary weapons, which in the period they did NOT. If a musketman got rushed, he could beat someone over the head with his musket. He didn't have a fine sword hanging by his side to draw.
To really reflect the period, ranged units need to lose their backup weapons and cavalry needs to be significantly more expensive. Horses really were and are a precious commodity because they have to be raised, trained and the men who ride them are paired with them. It's a bigger cost than you would probably imagine.
To be fair though, horses were like nuclear bombs in melee combat - a factor that few games, and mount and blade in particular have never really done justice to. A 1600 lb horse trained to kick you and trample you - running at you foaming at the mouth mounted by a guy with heavy steel armor... well, plenty of well trained armies actually broke and ran before the cavalry even got to them.