I like my strategy better
. With your strategy your going to stay fairly low stats unless you keep on replacing your entire army with stronger units. Which in the long run will take a lot longer and cost a lot more.
Though with the current casualty rate i do take pretty big losses, but its not going to be like this forever.
There is something i noticed though. I was bored and i did some calculations on excel. According to my findings i am about 1500-2000 higher in stats than i should be. I noticed that when i fight i lose pvp loot items that are far too weak to be in my top 1800 units. I then noticed that my stats were increasing slightly when i was getting these units, even though they are supposed to be too weak to be part of my army. Im assuming that a percentage of the stat of pvp loot gets added to your stats regardless and they are used in battle outside of the actual units that you take to battle. Right now they are giving me a couple thousand extra atk and def and serving as good cannon fodder.
Currently the weakest unit i should be bringing into battle is the border gunship at 5 atk 5 def. However, i very often lose tree snipers (3a 0d), trafficker gunmen (5a 4d), satellite trucks (1a 5d) and battle tanks (3a 4d). I even lose snipers (5a 3d) which i shouldn't be able to take into battle. So my conclusion is that PvP loot items contribute to your stats regardless and are used in battle without taking up any of the slots (in my case 1800 units max) for other units.