So as Ivo said,
1. If you want to stick with the Metro skin only, there is no way to set it to a color different from your Windows 10 accent color. But if you use any other skin, there is a "Menu glass color" setting on the "Menu Look" tab.
2. In your screenshot, the right column spacing/padding is bigger

The font size is the same. It is possible by editing the skin to have right column font or padding bigger. Tell me which skin you want it bigger for and I can try to edit that skin for you.
3. Metro skin in Windows 7 style is an exception for the glass settings because the "All Programs" treeview does not yet support transparency. Try other Windows 7-style menu skins with the glass only in the right side column. Or switch to classic style of the menu where the Metro skin can also have glass transparency.