I own 18 HPSSIMS titles and before that some Talonsoft ones so I have played many of the games. I recently downloaded the Tiller demos for Panzer Battles and Napoleonic Battles.
I was disappointed in Panzer Battles as it is basically Panzer Campaigns on a smaller scale. Even the sounds are the same.
My personal opinion is that these games need improvements in graphics and sounds plus gameplay has to be streamlined. For example, I am currently playing a small scenario in Moscow 41 PBEM. The sound for tanks firing is the same one for all tanks regardless of type. I understand that for hardcore wargamers the graphics and sounds are secondary but they do add to the overall experience. To illustrate this, I recently installed a mod for Wagram and the sound for cannons firing in the mod is amazing compared to what comes with the game.
Finally, I mentioned gameplay. I have not played a lot of the games I own because of the size of a lot of the scenarios. Looking at say the larger scenarios in Stalingrad or even Bulge 44 where there are hundreds of units and hundreds of turns which makes them unplayable. Having to click on each unit, then clicking on a target unit and then clicking to fire means thousands of mouse clicks to complete a scenario and it would take months maybe even more than a year to play. The largest campaign scenario I have played is the Salerno one in Salerno 43. I took one look at the Anzio campaign with it's 275 turns and said ugh!
Regardless, as a wargamer going back to the days of Avalon Hill I hope that some changes and improvements as per my comments above will be coming.