I like trying to figure out cards before actually playing them.

General stuff – One thing that's obvious is that losing a pack of Shadowmoor will impact most linear color-based strategies. You will have fewer targets to get full value from your Godhead auras, and your Duos will trigger less often. It will be interesting to see how people choose colors in SSE. I think you can go several ways with your land base:
– Mono-color or nearly so. You will probably get some solid cards late in Eventide that few others can play. You can get near-maximum value out of main-color effects, but your off-color effects will be distributed over four colors so you probably can't expect too much from them.
– Allied-color. I don't think it'll be that hard to pick up enough playables from Eventide if you're w/u for example.
– Enemy-color. Here you sort of pass on exploiting auras, slightly better mana, and certain uncommons and rares in Shadowmoor for the ability to always cast something like Unmake or Deity of Scars.
– Three-color wedge. Your deck will contain e.g. plains, islands, and mountains. You can get the mana-intensive cards from W/R and U/R in the third pack.
– Three-color allied. e.g. plains, islands, swamps. This might work out similar to a 5cg type strategy since you can play so many cards if you are willing to do "sealed deck mana".

A lot of this depends on just how rewarding the late picks in Eventide will be.

Retrace – It's always good to have something to do with extra mana in the late game, especially if the cards are useful earlier on. Things like Spellshapers and Invokers have historically been pretty good. I'm not completely sure if retrace is that special though.

Cenn's Enlistment – 3W
Sorcery (Common)
Put two 1/1 white Kithkin Soldier creature tokens into play.
Retrace

This is sort of similar to Icatian Crier, which was generally playable but not too exciting unless you had a few Fortify/Celestial Crusader type effects. As compared to Crier, you don't have to invest 3 mana and a card on a vulnerable 1/1 to get things started. On the other hand, four mana generally means you can't play this and another spell like you could with the Crier, or leave mana up for a trick on their turn. SSS has generally been fast enough and had enough evasion that making a bunch of 1/1s isn't that exciting. SSE is probably a bit slower but I'm not sure if it makes the difference. I would play this around 70% of the time in sealed if white, and maybe 25% of the time in draft.

Raven's Crime – B
Sorcery (Common)
Target player discards a card.
Retrace

This seems kind of clumsy, in that you rarely are in a position to safely discard land early on unless you are pretty flooded. It does have a benefit similar to Cinderhaze Wretch in the late game in that it prevents your opponent from sandbagging something big, unless he has several cards in hand and is willing to potentially trade them for your land topdecks. It's good that it only costs one mana. I would play this maybe 30% of the time in sealed or draft.

Oona's Grace – 2U
Instant (Common)
Target player draws a card.
Retrace

In formats like core set limited, cards like Treasure Trove have been powerful in the right kind of deck. I'm pretty sure this block is nothing like that. You have to activate this thing three times before it outperforms a no-conspire Ghastly Discovery. Especially if you're discarding your extra lands, you often won't be able to play whatever you draw with this. Still, there is a good chance you will win a stalled out game this way. Sealed 40% draft 10%

Flame Jab – R
Sorcery (Common)
Flame Jab deals 1 damage to target creature or player.
Retrace

I'm generally happy to play Scar. This is a little worse the first time, since you can't use it as a trick or stop a persist guy, but I think retrace more than makes up for that. You're not likely to actually get ahead on cards, but your opponent will have a hard time keeping their witch or x/1 evasion guy alive. Sealed/draft 80%

Monstrify – 3G
Sorcery (Common)
Target creature gets +4/+4 until the end of turn.
Retrace

I don't know what problem this is supposed to solve. If you have an unanswered evasion guy, you can speed up your clock pretty significantly, and after a long attrition battle when you both have smallish guys you can put your opponent into chump-block mode. I don't think these things together are worth spending a card on. Sealed/draft 10%