You're not "betting your life" on a TAF using an EIR, just the same as with an IR. That's just plain stupid.
At airways levels, METARS are available from VOLMET to give an idea of how the weather's panning out in the general region. Information services - eg London Information or Langen Information - are always happy to provide updated METARs and TAFs for any airfield you'd like to request. In a pinch, if he's not busy, ask the sector controller. You don't just sit there in the airway, following the purple line and praying that the TAF turns out right. During quieter moments you update yourself on how the actual weather is shaping up at your destination, so you can plan an early diversion in the light of actual conditions, if necessary. All of this is truly basic stuff for an IR holder, just as it should be for an EIR holder.
Really, if after all the training somebody cannot safely plan and execute an airways flight with a VFR sector at the end, it would be a total waste of time them doing an IR. An IR has lower minima, but it doesn't give you a magic wand to land if the weather turns out bad over a widespread region. You have to plan, monitor the trends, and make sensible decisions in the light of actual conditions as they develop.