Pack 1, Pick 1
At the beginning of this format, the pick would have been between Merfolk Mistbinder and Deeproot Elite, but I actually don't believe either of them is in contention. I believe taking a Merfolk card here is a mistake.
The Merfolk archetype is just not what it used to be. I would much rather be either blue or green and pick up a lord Pick 4 when I can be pretty certain the archetype is open. But if that's the case, why not hedge here?
You see, if I take Merfolk Mistbinder or Deeproot Elite here, somebody downstream could try to go into Merfolk, and the archetype can barely support one player, let alone two. So while the cards are powerful, both being in the pack makes them noticeably worse.
Outside of the lords, there are two solid removal spells in Impale and Waterknot. Between these two cards, Impale takes the cake by a reasonable margin. The one-mana difference is not worth the downside of enchantment removal, bounce spells, and the inability to remove cards like Tendershoot Dryad. Sure, Waterknot helps towards ascend, but I think that's marginal, as it also doesn't disrupt ascend for the opponent.
Pack 1, Pick 4
The Picks So Far:
This is a pretty phenomenal start to a draft. A solid removal spell followed up by two lords means the power level of my deck is going to be quite high. One mistake I see many players make in this format is to identify with a tribe, Vampires in this case, and just always take the tribe-synergy pick, even when the card is reasonably worse than the other options. Is the next pack one of these cases?
While Sun-Crested Pterodon is a much better card than Sanguine Glorifier in this format, with two lords, I think the Glorifier is the way to go. However, I also think it's much closer than many players think. And I want to take this time to address the following question: "What is the line for tribal cards versus generic good cards in Rivals of Ixalan Draft?"
Given two lords, that line in this situation certainly leans towards tribal cards. I'll say that I would take Sun-Crested Pterodon over Sanguine Glorifier if I only had one lord. I think the reason for that is consistency. Once you have multiple cards with high tribal payoff, the bar goes up. However, if Sanguine Glorifier were replaced with Vampire Revenant, I would take the Pterodon. Even with two lords, don't be blinded by tribal cards.
Overall, I would say that premium cards still should be taken over tribal cards. There's no reason to take Sanguine Glorifier over Luminous Bonds or Impale (except for some specific situations in Pack 2 where it fills a critical hole). But after that, the decision of "generic good card versus tribal card" is a function of the amount of payoff you expect to have by the end of the draft.