How about if a player rolls (6,6) for an Improvement he can choose to gain an extra half point of Strength?

This works fine within the existing ST scale.
For example, Kurt von Reigel the Human lineman gains + 0.5 ST for a new ST value of 3.5.
Against a rookie Orc Lineman he would get a 2 dice block, since his ST his higher. But against if that Orc lineman blocked him with an assist, he would get a 2D block since his effective ST would be 4, which is > 3.5. Easy peasy.
Cool or no?

Joe