Never in my life would I believe that I would see this mod on GoG 13 years ago when I first tried it. But that is such a welcomed surprise that I can only put in in my library and be happy for another 13 years of continuing enjoying heroes 3. If you already have Heroes 3 - don't overthink and try it now. And if you don't - what's wrong with you? Go get it now and then download HoTA.
It was groundbreaking when it came out but still pretty good even today. Pretty short unless you want to either replay on higher difficulty or try other classes but that is a plus in my book, to actually be done with a game after a weekend. My only real wish would be that they implemented coop from PSX for a complete couch experience. Otherwise, you should be able to find mods to completely change the game or just give you the QoL enhancements. It is a game from '96 so you should know what you are giving yourself in to already.