There are certainly arguements against the EIR and in favour of an IR. However, the specific concerns you highlight sound more about typical GA aircraft not being suitable IFR platforms, which I think is an unreasonably conservative position (of course we recognise a two crew, two turbine powered aircraft has much more instrinsic capability than a single crew with a single piston engine).
Almost all of my IFR flight could be flown with an EIR. It has the full knowledge and all of the enroute flying of the IR rating.
Flying in dead smooth air at FL100 above the overcast rather than bouncing around at 2000 feet makes flights much more enjoyable. However, the EIR does have the risk that the forecast VFR weather goes south so you need to divert (or shoot an emergency approach). Of course with an IR you weather could go below minimums and you be in the same boat (although it is very rare for the weather to go from 600 and 3km to less than 200 and 550m unexpectedly!)