I can not be alone in feeling a little annoyed at giving up defensive platforms, as Kix wants us to, to gain more base power to utilise the newer specials. But when you convert the 12, and then look at the next UG in order to gain the extra power required, only to realise that this only grants an extra 35k more power per platform. Then when you look at a WH UG this grants 135k more power. Why does something that Kix wants us to use to generate the base power needed it seems pointless and that it is better to UG a WH. The only thing that I can see that forces us into UG on a WH in order to gain the needed power is the difference between 2days 5hrs UG time on the power turrets and 16 days UG on a WH its almost like Kix wants us to coin
The upgrade on defense platforms doesn't increase your total base power. It just increases the power limit for that particular defense platform. There is no real purpose for upgrading defense platforms equipped with power transformers.
Warehouse upgrades increase the total base power, which is what it sounds like you are after.
The base upgrades are something to work on until the next OP upgrade. There are multiple things to upgrade so you can pick the route you want to take. Personally, I went for the Great Hall first, did 10x defense platforms with tokens I already had, and then moved on to warehouses for the extra power.
Food for thought, if you could pass that up to whoever has a need to know.