The problem we have with trying to match a scale with figures is the fact that the proportions are all wrong. Heightwise you can work on 28mm and try to come up with a matching scale, but the figures themselves are oddly proportioned, which helps make vehicles look too small. Couple that with unbased vehicles and based figures you get another mismatch, even more pronounced when figures are based on slotta bases!!!
Gamers tend to match vehicles with based figures, so by trying to say that something is "in scale" when you are working on this kind of mismatch makes the whole thing very difficult.