Greg discontinued support for this because he felt that for example the electron tubes are "too outdated technology" to make sense. So no, you cannot re-enable the feature.
However, you can use the gold you are now not needing anymore in the assembling machine (in the form of electrum) to craft circuits much more cheaply. For example, together with the wiremill, the cost of a standard circuit drops from 1 iron, 2 redstone, 2 copper and 6 rubber to 1/2 iron, 1/2 gold, 1/2 silver, 1 copper and 3 rubber. Advanced circuits go from costing 4 redstone, 2 glowstone, 2 lapis and a basic circuit down to 1/2 silicon plate, 1 gold, 1 silver, 1 glowstone and 1 lapis (no basic circuit required).
The one downside about the assembly machine is that it's mind-numbingly slow. You can solve that issue by building multiples, by adding overclockers (careful, upgrading GregTech machines works differently from normal IC2 and is non-reversible), or by doing what I do... simply give the machine a whole stack of stuff to process and then go do something else. I found that aiming to keep a buffer of 32 basic and 32 advanced circuits in storage will keep you covered for all but the most expensive of projects (four advanced regulators at once, holy circuit hell!).