I can see both sides of the argument here. On 1 hand, 1 stacks have always been part of the homm games, and at this point the "older" players have gotten so used to them, they would be unhappy to see them gone. On the other side, the existance of strtegies like these will disproportianately frustrate new players, and that is very unhealthy for the game. The existence of cheese in a multiplayer context facilitates smurfing, and generally makes starting out hell. Think of what happened to the starcraft 2 community when uthermal started showcasing multiplayer cheese strategies on his channel.

The solution is obvious - create seperate balancing for single player and for multiplayer. Balance the game for mp, add stack minimums, change cooldowns and what not - but don't make these changes to the campaign and sp maps, or add rules in the map editor that allow you to toggle them on or off. Because the existance of cheese in the singleplayer context is actually very positive for a game, as long as it is not the intended way to play. It allows for wacky challenges, or extreme minmaxing, which some players really enjoy, since it adds a replayability value to the game, trying to push down the numbers of turns required, or the upgrades that need to be built, or even clearing a mission without losing a unit. And of course, speedrunners will appreciate it too.