Regarding repeatedly buying the same hero in one day. I used this on this map to kill the strongest of the Four Horsemen of the Apocalypse, bound by the Chains of War, and save a few in-game weeks, but this tactic certainly doesn't make the player honorable.
And about not killing a key hero for the scenario when you can do it at any time. It doesn't seem like normal gameplay :)
Added 2 minutes later
But I also liked the map overall, even though I couldn't complete it, despite killing all the AI opponents on the map except for the inaccessible angelic castle.