Riven replaces [Point Strike] and needs crit chance and a neg which can bring you upto or just short of 100% crit chance. Smeeta buff will have a 10% chance to Redcrit, essentially raising total crit chance to 210%. Standard headshot multipier of 2.0x will become (2.0x1.75=3.5) and this gets better with greater weak spots. My favourite thing about this build is it will add straight lifesteal to nikanas with no mod requirement on them. I use this with my melee frames along with a CO [Nukor]. See Universal dot Zaw for a great rivenless [Nikana] Zaw:

Note: dps output indicated is inaccurate as this build deal high damage via multiplication including status.