Even though Crimson Vow has only been available online for a short time now, the format is shaping up to be awesome, especially for booster draft. In a few weeks there will be an Arena Draft Open that I'm really looking forward to participating in.
Here are my insights on the format from the drafts I've done in preparation.
Every color has access to removal, and in most cases multiple removal spells. We are in a world where Hero's Downfall is uncommon and Abrade is a common. No creature is safe. There are even multiple mass removal spells once you get to the rares. So, what does this mean?
Know the format, especially the common removal spells. Your opponent has a couple white mana up on your turn? Know that they can have Fierce Retribution or Piercing Light, and it may make sense to choose your attacks wisely. Creatures that gain value when they enter play by making a Blood token, or which offer extra value through disturb, are quite important because it's more difficult for your opponent to get good value from their removal.
In Crimson Vow I have yet to find a two-color pair I actively want to avoid in a draft, which is pretty rare. Normally I quickly develop color preferences and stay away from some specific color combinations, but in Crimson Vow I've had success staying open and drafting what comes to me. This isn't a format where identifying colors as "weak" will be particularly beneficial—if anything it may cause you to miss a deck you should be in for your seat.
If you see one of the multicolor uncommons and you are in a position to draft the two colors of that uncommon, generally try to do so. All 10 of these cards are very strong and really help define the archetypes of each color pair. I would go so far as to say if I don't have one of the multicolor uncommons in a draft I am pretty sad. First picking one though isn't nearly as nice as getting passed one midway through pack one, as that is a much clearer signal.
This is a format where you don't want to be drafting a color pair that someone else is drafting. If you have read the signals correctly, then if a multicolor uncommon in your colors gets opened in pack two or three, it should find its way to you.
Cards have different values based on what theme you are focused on. Whether it is blue-green self-mill or white-black life gain, cards are going to fluctuate wildly in terms of their value based on the deck you are drafting. My advice is to prioritize synergy cards that work with your archetype.
I have found three-color "good stuff" decks to be quite reasonable in this format. I would be careful about stretching your manabase too far—if you can be two colors with a splash, that is certainly more reliable than going straight three colors. There are certainly some rares that are worth splashing for, especially cleave cards like Path of Peril. With Path of Peril, I'd even be comfortable having only two white sources in my deck on the splash since the cleave cost is six mana.
In order to splash you really want at least one copy of Evolving Wilds. There's other good fixing too though, like Foreboding Statue and Honored Heirloom, as well as a couple green manadorks that can make mana of any color. Since green has mana creatures, it's better to splash out from a green deck than from other colors.
When I do go three colors, my decks are usually slower and based around rares and other good cards I picked up during the draft, including a high density of removal. Oftentimes your deck won't have a strong theme, and will play out in a more controlling fashion. I don't recommend being a three color aggressive deck, it puts too much stress on your mana.
Blood tokens are very powerful for Limited play. They do a really good job at making sure you have a reasonable draw. In a deck like Rakdos Vampires you are likely to have a ton of ways to generate Blood tokens.
In this deck you get to play a nice curve of creatures, and then once you start to have too many lands in your hand later you can loot them all away. Excess lands aren't really a problem with Blood tokens, and that's a big deal.
You can also loot away cards with disturb, or other spells if you need to find lands as well. In my decks with a lot of Blood tokens I normally play at least 17 lands since you can very easily discard lands later on with them. So far, I really like the way the Blood tokens play out, and have started valuing cards like Pointed Discussion higher as a result.
Self-mill is a thing, and so is straight-up decking out. The blue decks will often play cards that dig deeper into their library, but not a ton of ways to actually kill the opponent, which can lead to issues trying to close out games. Removal like Fear of Death will protect you, but won't stop an opponent from blocking.
In order to avoid getting milled out you can try to play more than 40 cards in your library, which I have done. If you can pick up a copy of Witness the Future, it goes a long way toward making sure you won't mill out.
The trend of devaluing combat tricks has become more and more prevalent over the course of recent Limited formats, but currently they are at an all-time low in terms of importance. Combat tricks have historically been a key part of Limited gameplay as a way to help your creatures set up blocks and force through attacks in combat. Not so much in Crimson Vow.
There are a couple reasons combat tricks have lost value in Crimson Vow. The first reason is that the tricks available in this format aren't super impressive. Beyond that though, decks care much more about having a high density of creatures. Oftentimes decks will need at least two creatures able to attack in order to enable training. In other cases, you want to be filling up your graveyard with creatures for something like Moldgraf Millipede.
I haven't wanted to play more than one copy of a combat trick yet. The best one so far for me has been Undying Malice as a way to trigger your creatures that make Blood tokens again when they come back from death.
There are many playable rares in Crimson Vow Limited, but there are a few that are certified bombs, and will win the game on their own.
I'm talking about cards like Dreadfeast Demon, which can get crazy really quickly. I've also really liked Stensia Uprising, Olivia's Attendants, Edgar, Charmed Groom, Olivia, Crimson Bride... there are too many to mention, but a lot of the best ones seem to be in red and black.
How does a bomb-heavy format affect a draft? If a player opens a bomb rare they are more likely to try to force that archetype. It gives you more incentive to stay open over the course of the first few picks if you haven't been lucky enough to get a good rare early in the draft. Grabbing an Evolving Wilds and staying somewhat flexible can mean you are in a good spot to capitalize on the good rares opened in packs two and three.
Exploit creatures are only as good as the enablers you have. What I mean by enablers are creatures you don't mind dying or sacrificing to an exploit card. Doomed Dissenter is a classic example of good sacrifice fodder.
There are a number of cheap creatures, including some that have disturb, that you really don't mind sacrificing. I have generally found that dedicated Dimir Exploit decks have plenty of sacrifice fodder, and really want as many creatures with exploit that they can find.
As you move out of the Dimir colors and pair either blue or back with a different color, your deck will likely not be as exploit focused, and the value of exploit creatures should go down. If you don't have a lot of creatures with exploit, enabler creatures like Biolume Egg can lose all their value and become unplayable. Only a few exploit creatures, like Stitched Assistant, can be played regardless of what other creatures you have.
As in previous Limited formats, enchantment removal in Crimson Vow is very vulnerable. In a format with a ton of exploit creatures, bounce effects, and even ways to straight up destroy an enchantment, you don't want too many copies of a card like Sigarda's Imprisonment. This isn't to say Imprisonment is a bad card, but you want to diversify removal. Oftentimes you will want to wait to cast Sigarda's Imprisonment until later in the game after your opponent has deployed most of their hand.
On the other side of the coin, removal like Flame-Blessed Bolt that not only kills something, but also exiles it, is quite nice.