No the scale is completely fine. There's no indication that they decided on the minimum specs then worked backwards to determine the scale. Game design usually go the other way. If anything, the scale is deliberate as Civ games have consistently reduced 'scale' and number of units since Civ3.
The requirements for Civ5 may appear to be steep for people who still think multi core processors are a new thing, but the specs are fairly far off from the types of games that tax modern PCs, so it is consistent with what Civ games have traditionally been in terms of system requirements.
The requirements for Civ5 may appear to be steep for people who still think multi core processors are a new thing, but the specs are fairly far off from the types of games that tax modern PCs, so it is consistent with what Civ games have traditionally been in terms of system requirements.