head to head
vs
Virtua Tennis 4vsWii Sports
Virtua Tennis 4 leans Execution (Pure Mechanics); Wii Sports leans Execution (Pure Mechanics).
Virtua Tennis 4Wii Sports
Axis by axis
Execution8 vs 6
Virtua Tennis 4 leans harder on execution: precise shot timing and positioning
Reads3 vs 2
Virtua Tennis 4 leans harder on reads: human opponents can be out-predicted in rallies
Variance1 vs 2
Wii Sports leans harder on variance: Minor physics wobble and CPU behaviour randomness
Optimization3 vs 3
Even - both lean on optimization about the same.
Two games can score the same on an axis and still test it in very different ways - read each rationale, not just the number.