Feno,
Within an increased OAT environment, can't one imagine that the subsequently reduced air density also reduces the aerodynamic controls efficiency which then might need to be compensated by an increased dynamic pressure requirement equating to a greater CAS?
Not really. The aerodynamic controls respond to dynamic pressure - EAS is a direct measure of dynamic pressure. CAS is equal to EAS if there are no compression effects. Below 250kts and 10,000' compression effects are
very small and generally don't need to be considered. Since VMC on most airplanes is less than ~150 kts (under standard testing conditions) you really don't need to consider compression effects.
For example: @ 10,000' and 250 kts EAS, CAS = 252 kts. @ 5,000' and 250 kts EAS, CAS = 251 kts.