That is one way to look at it. However, in most cases you will come out better with salamanders. I think if you are looking for flank protection alone, the razordon is the way to go. That is because they are made to stand and shoot. If they are charged, they will cause at least a little damage before they get run down. If I were taking razordons for this purpose, I would use the lore of light and make sure there were at least 2 razordons on each flank within 12 inches of my TG. That way, I could cast the light of battle to make them automatically pass the panic check caused by a loss of CC. You could also make them I10 WS 10 with speed of light.
Hope this isn't too confusing.