Fsx is old as hell;
skyrim looks nice but is also multiplatform game, which is not really demanding;
The witcher is also not very demanding;
take on helicopter is arma engine: single player not demanding, but when you would play multiplayer with a lot happening on the island, you will never run it sufficiently, even on 800x600 resolution, as the objects would simply burn your cpu to death;
Rof: cannot say, but is dx9 and scales pritty good and uses multicore. Dont know, how demanding it is, but you have a 1600x1200? monitor and run no native resolution? This tells much! Even 1600x1200 is just average detail/resolution;
Trainsim: holy crab, this was commodore 64? -> as demanding as farmerama ->today u get such things for mobile phone or as browser game
Total war: in high details also nice to look, but i think you do not play shogun2 or the other new parts in high detail -> also not demandin in the same way as cliffs of dover.
It simply shows, that you do not ask yourself, what the differences and priorities in all these games are -> this leads me to a result, that you seem to be casual gaming, right?
Do not get me wrong! You are right, that game code has a lot of problems, but cliffs of dover, even in a perfectly programmed version, will NEVER run sufficiently on your notebook. Sorry! But you are right about the problems, but the engine includes features, which you haven't seen in any other sim in this detail. Noone ask for fm in lockon, dcs or rof. You jist fly for fun and do not care, if this specific fokker is really flying like in reality.
The cod com is in this way really by far the most demanding comunity!!!!