The problem with RATs on some fighter aircraft was related to the airspeed required to keep them going. With the A-7, among others,you needed about 200 knots to generate the hydraulics needed for directional control,and at 200 knots you landed on the nose wheel which woukd then collapse. If you tried to slow up more than that,you lost your hydraulics.
Back when the F-16 was being designed, a chemical backup system was wanted and the EPU seemed a perfectly reasonable thing to do. They had their choice between using hydrazine or hydrogen peroxide. Either one run through a catalyst would produce gas that would spin up a turbine. The hydrogen produced superheated steam and ammonia with traces of hydrazine,the hydrogen peroxide produced superheated steam and oxygen with traces of hydrogen peroxide. The hydrogen peroxide (80-90%, not the 3% you get at the drugstore), was more corrosive and tended to explode and create fires if it hit anything like grease. The hydrazine was safer....but then came the EPA and OSHA.
They wanted a standard for allowable exposure of hydrazines (note the plural). While straight hydrazine is relatively benign, some of the hydrazines used in missile (Titan) and rocket fuel, like mono methyl and unsymmetrical dimethyl hydrazine, are fairly toxic. But when they came out with a "hydrazine standard" that lumped them altogether, the law now required for any hydrazine discharge, even just plain hydrazine, to be handled by the same standards as the most toxic of the hydrazines.
I wouldn't go so far as to say the F-16 EPU issue is much ado about nothing, but it's definitely a case of regulatory overkill.