Yes, what you have done so far looks fine to add shipping based on the total price, but will need to be modified in order to exclude items from the shipping.
in order to exclude items from the shipping cost, you need a new column to mark which item should be included and which items that should not be included.
in the thread I linked to, you create a new column named freeShip.
Items that should not be included in the shipping cost will be given a value of 1 in the add to cart button, items that should be included in the shipping cost are given a value of 0.
you then need to use the subtotal of items where freeship has a value of 0 in the shipping cost calculation.
which specific part of this are you having trouble with?
without knowing where you are getting lost, all i can really do is reiterate the description of the process. If you let me know which part of this does not make sense i can do a better job of addressing the cause of the confusion.
No, eCart 5 will not simplify this, it will be done exactly the same way in EC5 as in EC4 (or even EC1, 2 and 3).