AI4 might be more profitable than AI3 when you grind both with Mono Aether. This deck is designed against AI4, not 3. Most succesful AI3 grinders are generally rushes which can destroy opponent before it even set up while tis deck is example of stall..
The deck wasn't designed against anything, it was simply the first example of a good rareless, Unupped deck I could think of off the top of my head. It immediately eliminated what was put forwards as a reason not to farm AI4 - the cost of making a deck which could grind AI4. Well, the cost, in this case, is exactly the same as for grinding AI3.
And another thing: don`t compare gold earned per game but gold earned per period of time because this is what matters while farming.
I did:
So, AI3 had a total gain which was 60% that of AI4, with a TTW that was 76% that of AI4's.
[...] it seems that AI4 is more profitable in terms of total gain vs. TTW without even taking winning Upped cards into consideration.
Farming AI4, from the testing I've done so far, had a higher
gain per turn than farming AI3 - and that's
before taking in to consideration the possibility of winning an Upped card and the extra value that would bring.