Personally I wouldn't be happy with any procedure that was as lax as to simply climb to MSA without any form of horizontal guidance. Especially in the Oban area!
I think what you are proposing 2D is probably the only possible way that you could have any form of semi-IFR procedure. It is still VMC necessary and cannot sustain a daily service, but it would at least be some form of help.
An NDB in that area would be subject to so many errors that it would be virtually useless. Maybe the CAA could trial a GPS approach for use! It would be the perfect proving ground as basically not much else would work, and if ti was successful, then it should work anywhere!