Yes your right. On the og evo wimax was a battery killer for sure and although i lived in Las Vegas (where wimax was strong) it totally killed my battery.
On our new evo lte the Lte network does not tax the battery nearly as much as wimax did. Even if you dont live in an lte area you'll still see minimal drains due to lte. But.....
Even if i get 5-10% more time during a charge cycle its well worth it to me to have it off. Instead of 20 hrs i maybe get 22hrs.
So in my experience i keep lte off and wifi and gps and 3g lol.
If you add a toggle to your screen where you can switch on 3g only when needed you will see the best battery gains possible for your phone