It is true that both games look similar. The reality is that both games are inspired by one of the most famous war games on board in history: Advanced Squad Leader (published by Avalon Hill in the USA for the first time around 1974, with the title Squad Leader).
Many of the people who have played Advanced Squad Leader (ASL) see Tigers on the Hunt (TotH) and Heroes of Stalingrad as the two best approaches on a computer.
At least I see it this way.
Finally, I have decided to publish "Heroes and Leaders mod," using the Heroes of Stalingrad game platform, because I see that, although their game mechanics are not as respectful with the rules of ASL, Its solutions include many more of the elements of the ASL game and are infinitely better than those offered by TotH.
The developers of Tiger on the Hunt have made a great effort to get as close as possible to ASL, but they have stayed halfway. Heroes of Stalingrad is several steps ahead. And I do not mean only the management of the graphic environment, which is excellent in Heroes of Stalingrad (in Tigers on the Hunt the graphic environment is very simple), but also in regard to Artificial Intelligence.
Richard, I also agree with you that "it's a real shame that a DLC / follow up was not released," but maybe it's not too late.
"Heroes and Leaders mod" may be just a modest step to keep the game alive, but it may not be the last .........
To be continue,.....
Regards to both.