Gunna have to disagree with you here on the part about every mastery should be good in 1v1 and I think most people will feel the same. Any mastery can be good for 1v1 depending how you use it. Is fire/light a good 1v1 mastery? Usually no, there are better options, but in a team fight fire/light can be a heavy carry with fire dot and light stun-lock. And that there IS the balance. Str Light/wm is a 1v1 build and excels there but in a large group their abilities quickly become outshined by the fire/earth and other high int AoE jutsu’s that make getting close difficult. There are always exceptions but the balance in the game is having certain combo’s and masteries that excel in either team fights or 1v1s, or support.
Fire/Light can be a good mastery combo if used right, any GOOD lightning user will know that your opponent is going counter/sub your chidori, so you must counter play them. Landing chidori is basically a death sentence if followed up on properly, treat it as such and quit demanding a buff when chidori doesn’t need it.