1. The understanding of electricity in Halacha has changed over time, as you noted. That is not radical, merely factual. Nowadays we accept that it is assur to switch on/off on Shabbos and Yom Tov.
2. I am pretty sure that I know exactly what the oven is (and I had one myself, as I mentioned) and that the halacha is as I said, but I am willing to accept that you have such a psak for yourself. I have one question for you though, and that is why do you think that your oven is any different than a modern oven when it comes to lowering the flame? Here I’m not talking about turning it off, as there is a clear difference in that (the modern oven will have no flame but the old one will be reduced to a pilot) – I am talking about simply lowering the flame such that a flame is still there. I would think that there is no difference. Yet, most poskim do not permit doing this even to benefit the food. Why then do you think you can lower your flame at will?