If you understand our line-up you see that all the models we carry are classified as Game Improvement. Actually they are all in the Super Game Improvement category or Ultra Game Improvement category of the Maltby Playability Factor. The MPF is based on the mass and dimensional characteristics of a club head and we have measured hundreds and hundreds of all models of irons over the years from all manufacturers and have them listed in our MPF database. I only mention this to address your statement that implies all game improvement irons have a thick topline, or have the back edge of the head show in the longer irons. I understand you thinking this as that has been what has been the common observations in the past. However, those are not automatically inherent features of any design called “game improvement”. Those features do exist on some, no doubt, but you can have GI, SGI and UGI irons that have thinner top lines and no visual back edge in the long irons.
Now that that is cleared up, the KE4 S, KE4 Tour and the KE4 Max on the #4 iron, which is the lowest lofted iron in the set, you can see the back edge of the iron very slightly towards the heel. The TS3 I would call it minimal if even noticeable. The same for the STi. TS1-IM, TS1, TS2, TS4 it is not visible, at least to me. Remember, whether you see it or not depends partly on how you set up and on your dominant eye. I am basing this on having just gone into my shop and looked at all of them in the address position, my address position.
Hope this helps.