In my compamy, Cabin Crew are trained that it is their responsibility to check outside for hazards and therefter make their own assessment of which slides/exits should be used.
On balance, I think this is best, the CC can best SEE what's going on outside, they should not be reliant on FD's possibly incorrect interpretation of instrumentation, or perhaps the incorrect communication of correctly intrepreted instrumentation.
In any case given a sufficiently hazardous situation, the CC can initiate the evacuation themselves. Probably more importantly, if the scenario is sufficiently dangerous, the pax will be out the unguarded emergency exits, in the pub and enjoying their first pint by the time the emergency evacuation checklist has been completed, and if you don't believe the latter to be true, you've never seen one for real.
Of all the sim check items most gloriously and regularly f$%ed up, emergancy evacuation must be right up there at the top of the list.
Leave the decision to those who can best assess the hazard.
No doubt there will be many who disagree.