It's easy to call someone a liar on the internet, isn't it, brave BlackRainZ? I have never said that I have won the game in .98. Maybe you should work on your reading comprehension. I am very careful to say what versions my games have been in. Given that the latest version nerfs everything but heroes, I am pretty confident in saying that I can still win the game without cities.
How to win without cities? There is only one way right now - Master Quest. Before, you could do it by razing enemy cities, but now you cannot, because you have to hold them for too long.
As for winning with heroes only, you could check some of my three playthroughs: .913, .915, and .952. I do not think I have build even one unit except pioneers in any of them. Of course, they are all of earlier versions, and the latest does not get all the way to victory. It still has multiple level 20+ heroes by turn 60.
The strategy for powerful heroes on any difficulty is: buffs, especially regeneration, high initiative, mobility. On high difficulties, before level 8-10, you may need to kite because the enemies get three to five times the hps, but once a hero is level 15 or so, nothing in the game can touch him, let alone take him down.