Will critical damage runes (not critical strike) enhance Talon's Q critical strike damage?

Yes and yes

Critical Damage runes have a cost in the form of an either/or purchase between critical chance and critical damage. That's called opportunity cost, and is the more interesting model of shopping for the gamer.

The point at which one is better than the other is a part of the current environment.

Logically it would be yes,but some people who tested it on PBE said there was no difference in dmg with or without the passive from IE,which s**ks :/ if this is intended

if you have crit damage runes then when you crit strike then your crit should do more damage... but here is the kicker to crit... with out high crit chance you wont crit as often so with less crit chance you do less damage over all... and crit is an amplification of physical damage which doubles your physical damage

so lets use #s for exmaple: you do 100 damage with out crit strike with crit stike happens your damage goes from 100 to 200 and with IE its 250 damage

but you only have crit chances of 5% compared to 50% will you are gonna do more crits at 50% crit chance over 5% therefore do more damage

so if you take crit damage runes and lets say its +20 crit damage and you crit for 200 damage +20 from runes thats 220 damage but if you dont have crit chance to increase of often you crit then your runes are subjected to the RNG of crit and you wont get anything from them on a regular basis

would be better off taking AD runes that when you do crit you have more ad so the physical damage is higher based off ad

Yes, and Randuin's will reduce it.