BFZ: Converted mana costs of colorless cards

A U/B exile/process deck I recently drafted had more 5-drops than I would have liked, so I’d like to determine whether there’s a glut of good 5-drops for that deck. Almost all my cards in that deck were colorless, so we’ll just look at colorless cards for the purpose of this analysis. Since there are also 2 other archetypes that rely on colorless cards (U/R devoid and B/R aggro), we will also examine those.

The 3 tables below list the most important cards for each of these 3 archetype by converted mana cost and rarity, with bold indicating that a card is particularly strong in the archetype. I’m more concerned about the first few turns of the game, so the lists do not include splash cards and finishers. I’m hoping this analysis will help me decide which converted mana costs I need to focus on for each of these 3 archetypes in order to end up with a good creature curve.

Some observations:

• U/B exile/process does not have an unusually high number of colorless 5-drops, it was my deck that was unusual (it had 2 Oracle of Dust and an Ulamog’s Reclaimer, plus a Windrider Patrol).
• In addition to Mist Intruder and Culling Drone, U/B exile/process decks also have access to 2 uncommon 2-mana non-creature spells that can exile cards (Horribly Awry and Transgress the Mind). Similarly, it has access to Complete Disregard, Grave Birthing, and Spell Shrivel (all commons) at 3 mana. Unlike ingest creatures, these only exile a single card, but they can nevertheless get your first processor online.
• All 3 archetypes have 4+ playable 3-drops at common, so you should prioritize 2-drops when drafting. This is especially true for U/R, which has another 4 playable 3-drops at uncommon, especially since a number of its common and uncommon 3-drops are particularly strong.
• All 3 archetypes also have a number of strong mythics and rares that cost 6+ mana that you will rarely pass. However, U/B has a number of strong uncommons at that mana cost, so you probably shouldn’t prioritize those cards unless you really need a win condition.
• Sludge Crawler is the only playable colorless 1-drop (Salvage Drone is unplayable, and Endless One will rarely be played as a 1/1). It fits in both the B/X archetypes that want colorless creatures, but I don’t have enough experience with it yet to determine how playable it is.