We have had the same discussion for various other Sense based devices. The new calculator style started after Sense 3.something and has continued with Sense 4.0 and Ice Cream Sandwich.
The Sense calculator widgets do not have quite this same style numbers, so if you can spare a homescreen it might be a worthy work around.
Quick Tip: if you turn the phone landscape within the calculator application you will gain a few meager higher arithmetic functions; Sin, Cos, Tan, Pi, etc.