The process of modifying the watch is very gratifying in itself. For most, a "Franken" is not about getting it to be more like gen and saving a little money in the process, it's about the journey.
To create a franken you must gen parts that are often difficult to come by, sometimes you need to modify parts of the rep case to make the gen crown fit or that gen bracelet. You've got to figure out how to attach the gen dial to the A2836 movement because the dial feet are in the wrong spot. Like you mentioned, you need a steady hand, a little know-how, and a lot of determination.
At the end of the day you have a watch that means more to you than any rep or even any gen, this new watch is now a part of you!
I hope this helps.