I feel like this will lose you the game by land starvation as often as Dark Confidant will lose you the game because you lost too much life to its ability.
I think the card is intrinsically powerful (repeatable card filtering and removal, high starting loyalty if needed), but that's only piece of the puzzle when creating a drafting environment. I think the hardest knock against this card is its casting cost, which already has a large pool of strong choices. On top of that, the disparity between each 4-drop's power level is not as great as it is between each 2-drop in these colors. In the end, I think adding Lightning Helix over random 2-drop creature will always make your deck better than adding Nahiri over Hellrider/Hero of Oxid Ridge/Hero of Bladehold.
Tl:dr - All the current four drop options are pretty close in power level and I never have a hard time filling that slot in my draft decks. The same is not true at the 2-drop slot.
The changes look good! I'm a bit curious about your decision to make a new section though. Why not just lump these into the free-form section so you're not forced to play 10 colorless cards if certain ones underperform.
Without testing, I feel like this card might be house enough on curve to justify the slightly worse alternative of playing it turn 4 or 5. Any sort of library manipulation or recursion makes this even sweeter.
I think the most interesting part of this card for me is the potential to encourage a new archetype, and have that archetype be focused around a color with a pretty singular identity.
Tl:dr - All the current four drop options are pretty close in power level and I never have a hard time filling that slot in my draft decks. The same is not true at the 2-drop slot.
Just got word that my latest alters from Modfly have been completed... behold the OG Might MORPHin' Power Rangers
Of course testing may prove that very wrong.