first of all, the freeze spells are used in that strategy not to stop infernos from attacking the army, but only to stop infernos when they lock on to heroes. You seem to think you already know it all and this may be part of the reason you are having trouble.
Second, While I agree that most troop AI's are primitive at best, this is made up for by the massive amount that offense is overpowered in comparison to defense. A high ranking player can 2 star a maxed out base with any layout, this is why when you look at the leaderboards they all have so few defensive wins. There are actually quite a lot of variables that effect win / loss, the only reason the videos of top players look repetitive and simple is because they have perfected their strategy to react to and overcome any surprise or obstacle that pops up during a fight.
While picking off outer buildings to get 50% is one strategy, it is by no means the only strategy or even a very popular one at that.
If memorizing troop deployment / spell usage is so easy that it garentees a win every time liek you say it does then what's stopping you from doing the same?
I originally suggested you change your strategy, but after seeing how dismissive you are being to everyone's posts it looks like you more so need to change your attitude. If you assume you already know it all then you wont learn how to improve and thus won't get better.
Maybe we could just drag troops dropped to anywhere we want on the screen, and get them to attack any building we desire
The OP was poorly thought out and reflects badly on the poster and then he goes on the offensive when people contribute (constructively) to his rather daft ideas and thread.