For anybody still playing this and trying to get the Victoria Cross achievement (main campaign in less than 35 hours)...

I tried a 'speed run' with no recon missions and completed nission 26 (last Berlin mission) at 26 hours (22 hours after mission 23 before going to Berlin) - with the last mission taking less than 2 hours. My characters were between level 34 and 39 after mission 26. This included watching all of the cut scenes but accelerating dialogue (only because I can read faster than the characters speak!). I also found all special swords and all Valhalla reports so time is not really an issue.

However. by not doing any recon missions there are some valuble skills that you miss - for example light-footed and find weakness, however clearly there is enough headroom to clear selected recon missions according to the skills you are after. You should be able to spend 5 hours on recon missions and still have plenty of time to complete the main campaign. Note that every recon mission is still available after mission 26.

Hope this helps - great game!