The blue splash in Temur should be for Radiant Flames, Nissa and the aftermath of Spring//Mind mostly IMO. Maybe you want to splash one or two more cards like Altered Ego or Kiora, but these should be the main ones.
Weaver needs more commitment to Blue than you're comfortable with I think, seeing how you need Blue turn 3 for it to be any good.
Red is in for Radiant Flames, Harnessed Lightning, maybe a 1-mana removal spell in small numbers and the Aftermath of Heaven // Earth . There are some bombs you may want it for as well (Omnath, Chandra).
Similar, Sultai would run Black for Fatal Push, Languish, maybe Murder or Never // Return (or even Rags // Riches) and possible bombs like The Gitrog Monster or Sire of Stagnation.
Agree here. While the mana dork route seems the most attractive, I feel like it just doesn't line up with the current meta. Relying on mana dorks to ramp you means you likely don't want to be running sweepers, which significantly improve the matchup against aggro. The matchup against control is likely to be bad no matter what we do (since we lack stuff like
Banefire, unless you want to try and go the
Exquisite Firecraft+
Geistblast route).
Adding Red to the list adds some extra early removal and access to
Radiant Flames,
Kozilek's Return, and
Heaven // Earth.
Adding Black again gives you early removal and access to
Languish and
Yahenni's Expertise.
IMO Ramp should be ditching the mana dorks in favor of instant/sorcery/enchantment based ramp effects and should be packing as many sweepers/early removal as they can afford to run without interfering with their ramp:payoff ratios.