I'm of the mindset that the only swaps that really make since are GC swaps since a comparable factory option wasn't available here(plus the added weight savings with that chassis). While not my cup of tea, I can see the appeal to bugeye STI swaps for the lack of a factory option too.
Anything other than that it really has to become much more of a financial decision because you could buy what you are building from the factory. From looking at prices on the used market, you could maybe end up ahead for an STI swap into a newer RS if you got a killer deal on a wrecked STI and did all the labor yourself. That's assuming you're planning to keep the thing forever because you'll never be able to sell it for anywhere close to what an actual STI will go for. Or at least long enough for the cheaper insurance to make up the difference.
WRX swaps or paying somebody labor for the STI swap, forget about it. Like the OP was told prior to starting this process, sell your RS and buy a WRX or STI. It'll be cheaper from the start, and have better resale in the long run. If you can't get out of your current car because you're upside down, then throwing a bunch of money into it that you'll never get back is not the smart financial choice.