Yes, it does complicate matters. However, if we can find the exact problem and write a new registry automaton specifically for Windows 7 then we'll get rid of this problem.
And I tried OpenTTD. It is extremely close to TTD but at the same time not exactly it. Furthermore, it is not even finished even though it been years in development.
Frankly, after trying OpenTTD, I don't really see a reason not to go with the original. Except maybe if you wish to try out extremely huge maps.