Seeing someone with The Ur-Dragon as their commander, for instance, is usually a sign youre going to have a bad time
Dragonfly Pilot would fit well in a Vehicle-centric deck, particularly one that leverages both white creatures and the synergy of crewing vehicles for aggressive strategies
Alharu, Solemn Ritualist and Sengir, the Dark Baron Perhaps the spendiest of the pairings (so likely played in a lower-power environment), this one will be all about sacrificing creatures and then doing things with the Spirits which Alharu creates
Turning this around though you are more likely to play cheap low power spells in a deck if they have flashback and may be used for extra value again later
On average random is probably the most effective but it is obviously more
Looking at the pre-sale prices, this expected price drop already appears to be happening