Yes, if the drives are good then its likely the way I would go also. You would need one of the above mentioned controllers though. The YAPSC can do Step/Dir to analogue but I dont know much about them and have not heard a great deal but a search on the CNC Zone may bring you some answers as I think that is where most activity on them is.
The KFlop/KAnalog would maybe be the way I would go although DSPMC also seems good but more expensive. Having said that I have a 4 axis Galil here that I bought on eBay a while back so maybe that would be the way for me.
Suppose it all depends on you, have a look at the Kflop/Kanalog and DSPMC sites and see what you think, the Galil site may not help you much but there are sections here for Galil which should give you info, also section for DSPMC but dont think the KFlop/KAnalog has a section here.
How does your turret work? is it all hydraulic or standard DC motor or servo? Also tailstock, is it hydraulic or servo driven for positioning?
Hood