I may be wrong, but if i am correct, the stats given on speed on wild creatures (not flyers and alike) doesn't increase their speed stats. My suggestion is not making thoose creatures being faster in the wild using their points given on speed stat, but instead making them have no points put on speed stat while was a wild creature, on the same way it works with flyers and alike, so they have no unused points.
In case this also happen with oxygen stat, make creatures that doesn't use oxygen stat not having points put on oxygen stat as a wild creature too.