You mean the mechanical parts for the conical scan which rotate either the feed or the antenna? Is this a confirmed fact, that the 347G system does not use a monopulse feed? The new radar still has the mechanism to rotate in elevation and azimuth.You also have the collateral benefit of reducing mechanical parts which improves the radar's reliability, less maintenance, less mechanical wear and tear ...
As a side note, replacing mechanical components with electronic does not by definition improve reliability. There is no shortage of examples where going electronic reduced reliability.