The Invisible Mekansm
A build for the most inconspicuous support hero: Riki. Yes, counter-intuitive, but I'm serious.
Riki does not need much to have an impact through his strenghts: high damage, high mobility. By forsaking farm and turning into the Mek carrier you get: farm for a more reliable core hero (not countered by dust/gem); a support that is capable of disrupting teamfights with Smoke, drawing focus fire, forcing resources (enemy detection) and dealing good damage; and a true scout. Try it, it makes sense.
This update will bring with it two huge, huge buffs for support Riki: first, the cast range for Smoke Screen is significantly larger. Second, using items and casting spells no longer breaks your invisibility! All items with good active effects become more interesting, including the new Linken's Sphere.
You're going to farm: pulling neutrals, like a regular support; defending/pushing towers with your team, like a regular support; and, after laning phase is over, if your team finds it hard for your carry to farm outside tier 2, make use of your inv to get the ocasional last hit and escape safely.
Try not to KS, try not to feed. Pay attention to detection. Once you have the Mek, hover around your carries, scouting, ready to jump in, smoke, use Meks, hit somebody. Remember: Smoke has a 13s CD and 6s duration, so there should be a Smoke up for half the time of all teamfights during the game!
Support Riki is suprisingly durable. Often I am the last one to die in a match. If a Gem happens to be in your team, you might want to carry it, true to your scout nature.
Keep in mind Riki is (probably) not an *optimal* support hero. But he can certainly play the role! Plus, you get bonus points for the surprise factor. Nobody expects the Invisible Mekansm.
P.S.: lots of Russians (or Russian-equivalent) have been commenting and messaging me about how this is heresy and Riki should build Sange and Yasha and Diffusal. I think stacking agility as Rikimaru is some sort of religion in Russia. Anyway, don't let the 'rating' fool you, this build is - at least - functional, and situationally viable.