A note: Something I do dislike about Dire Fleet Daredevil (and actually also about Abbot of Keral Keep) is that it's not a "real" two-drops. As in, you need mana to use their abilities so they don't actually allow to curve out or stabillize on the first few turns. Besides being quite fun in draft, it's one of the reasons I'm looking into it for cube. Having a 1/3 body that provides value over time is pretty comfortable.
I've actually slotted Snapcaster in as a 4-drop in my lists before because of this very reason!
Ugh, this "triggered" me for whatever reason. Must be due to my insomnia...
This reminds me of a statement quoted by another cube enthusiast that I try to follow:
“Randy Buehler was running the FFL at the time, and he gave me a deck to play. In it were four Grizzly Bears. I didn't think anything of it at the time. I then went on to go 4–0 that week. I was the only person with an undefeated record.
During my last match, Randy watched. At some point late in one of the games, I played my Grizzly Bears. After the match was over, Randy informed me that the Grizzly Bears weren't actually Grizzly Bears. They were proxies for Kavu Titan. Armed with this information, the next week I went 2–2. Suffice to say that the R&D guys thought this was the funniest thing ever. The lesson I learned was the importance of using the Kavu Titans as 2/2s. When I was aggressive with Kavu Titan, my deck performed much better. When I waited to maximize the Kavu Titans as 5/5 creatures, I lost much of the aggression of my deck and thus some of its power. Week 3, I went 4–0 again. - Mark Rosewater”
This resonated with me a lot when I had time to design my cube, and hell, when I use to play Abbot of Keral Keep back when I did play Standard - while nice to get those additional abilities/triggers, when you are curving out or being aggressive, playing them as two drops are more than acceptable. Abbot is a fine 2-drop, not amazing, but in an aggressive tempo/spell matters/burn deck, having him come down on turn two, then turn three swing for 3+ power is still decent. Same with Direfleet Daredevil- a 2/1 First Striker on turn two on its own is fine, and does well with equipment or various other buffs going forward throughout the game. Using Snapcaster Mage as another example - it's just as serviceable as a Ambush Viper (though, admitting, Snapcaster Mage is not an aggro card, so not the best example) if you are on an aggressive bend.
I guess what I'm rambling about is that I think it's counter-intuitive to state these kinds of two drops are not true two-drops because you cannot use all of the abilities of a card. I think it's best to look at them as "Two-Drops-with-additional-upside-later-in-the-game". I think any other mindset is marginalizing the cards unfairly.
...Er, anyways - um, I do vote for Burning Prophet if you are going midrange/controlling though. Getting added value per spell cast throughout the game is solid (plus that card and Spellgorger Weird have been Beast Mode for me in WAR drafts, so chalk this up to recency bias).