Yes the airplane could then be made smaller since the plane could be smaller and still retain the same wing loading. At the same time the reduced size would have less drag and the plane would fly faster to boot.

But then we wouldn't have a Cub anymore. It would be something new and likely much like some of the more Cub like but smaller ultralights out there these days. One example being a Murphy Maverick that just happens to be made local to me.

http://www.murphyair.com/murphyair/A.../Maverick.html

Very Cub like in concept but smaller and lighter and probably flies faster.

Maverick specs-
GROSS WEIGHT 950 LB.
EMPTY WEIGHT 395-460 LB.
G-LOADING (NORMAL) +5.7 -3.8
POWER RANGE 53-65 HP
WING SPAN 29' 5" (std) or 32' 5" (extended)
LENGTH 20' 8"
FUSELAGE WIDTH 37"
WING CHORD 60"
TAIL SPAN 106"
AIRFOIL 4415 (MODIFIED)

J3 Cub specs
General characteristics
Crew: one pilot
Capacity: one passenger
Length: 22 ft 5 in (6.83 m)
Wingspan: 35 ft 3 in (10.74 m)
Height: 6 ft 8 in (2.03 m)
Wing area: 178.5 ft² (16.58 m²)
Empty weight: 765 lb (345 kg)
Useful load: 455 lb (205 kg)
Max takeoff weight: 1,220 lb (550 kg)
Powerplant: 1× Continental A-65-8 air-cooled flat four, 65 hp (48 kW) @ 2350 RPM

Yep, that pretty much holds water I'd say.

And I hear you about the "formula" of the designs. It was quite noticable in pattern for example that the wing area shifted as the emphasis on how the models were flown shifted. Or maybe it was just the fuselages got so darn big.....