I finally made a Rift War Scepter for my assassin, so I'll give you my 2-cents here.
she has a +15/-5 nightwings but not facet shield, and I must say I'm a little disappointed with the orb damage. don't get me wrong, the effect is stunning, but it seems like the bark is worse than the bite. I didn't build exactly according to your guide here, I made a Chaos Ice hybrid. 20 points death sentry, light sentry and shock web with an infinity merc is more than enough by itself, you wouldn't need rift at all so the effectiveness of rift would be overshadowed. She was hitting 1400 chaos ice (since i have trap sk's not martial arts. even that ice orb seemed weak. I believe that is due to not being able to sweet spot the orb like a sorceress could, the assassin is limited by where she can cast from, it takes more to setup your attack to even get the orb to go the right direction at all. Your guide says to use shadow master, personally dislike her because of the mindblasting/convert, it only slows you down. these points could go into LS synergies or even fireblast as far as I'm concerned. I also
Not to say rift sucks, it's just that the skill build does not suffer if you choose to not use it. I know, your aim was to be concise but there are two weapons that I feel are worth mentioning which have more to offer than rift.
1) Lawbringer phaseblade works wonders, if you haven't tried that on a kicker, I highly recommend it. decrepify + sanctuary and built in life leach are great safety and damage boost for DS and merc. the rest in peace gets annoying, but it works fine if you and your merc are attacking the same monster, let him finish while you lay out some DS. this works great with more synergy points in LS, and bosses go down quick with decrepify, and sanctuary makes short work of wisps and vampires, but mostly you use it to cast decrep and let DS do the rest.
2) Death phaseblade is also a great weapon. glacial spike is awesome for safety. back me into a corner please. you get built in mana leach and a nice damage boost from ds and cb, however the glacial spike can break corpses for the same effect as rip essentially. love the glacial spike with blade shield. could have made in an eth zerker for a nice blade fury hybrid, but that seemed unnecessary. I like using max fireblast to get more out of each DS and shock web and have something to use against the stone skin unbreakable lit immunes.
according to faqtoids library, critical/deadly strike do work with kicks.