You made me look at white common and uncommon two-drop creatures in Theros block. There are eleven of them. I'd rank them this way:
Better than the Sun Guide:
Phalanx Leader,
Akroan Skyguard,
Cavalry Pegasus,
Leonin SnarecasterComparable to Sun Guide:
Battlewise Hoplite,
Akroan HopliteWorse than Sun Guide:
God-favored General,
Vanguard of Brimaz,
Traveling Philosopher,
Setessan Battle PriestTwo-drops are very hard to get lately, everybody picks them highly. The quality tricks are in Theros (unless you're blue), so the BNG two-drops should be even higher picks. In fact, if you plan on being white, unless you see the Skyguard,
Ghostblade Eidolon and maybe the
Elite Skirmisher, you should pick the Sun Guide.
But what rating this translates into, I don't know. 2.5 seems a bit low, but it's just a feeling.