However, NO-ONE can eyeball a limiting OEI departure in a critical terrain environment - the subtended angles are too shallow for reasonable human perceptual considerations (I may be on suspect strict physiological/psychological ground there ? perhaps some of the relevant techo specialists can advise if the research literature indicates that the typical human can discriminate to that sort of minimal angular displacement ?) ergo, either one has had the takeoff analysed or one is on dangerous ground - and, potentially, literally.
Having done a lot of flying in areas of significant terrain, I'd really have to agree with that. I did a mountain flying course some years ago and in the ground school, one of the instructors circulated a research paper detailing human limitations when assessing angles, horizon references and the like. It was an interesting read and from memory somewhere around 20:1 was the cutoff beyond which it became complete guesswork and that was with no slopes confusing the issue.
I'd also agree with following the OEI procedure, even if CAVOK. In airline ops, we generally aren't given enough information to be able to second guess the reason(s) why an ET or just maintaining the published SID is necessary. What segment(s) are the obstacle(s) in? Is there something like a mast which you won't see until you're nearly on it? If you are below the top of the local terrain it is
very difficult to make an accurate judgement on whether you're going to clear it or not. Add in the complications of dealing with an emergency at the same time and I think I'll put my trust in the procedure designers.
If it became obvious that the failure was a complex one outside the normal parameters (flap/slat damage, bird strikes on multiple engines, gear not retracting, etc.), then yes, I'd be prepared to throw away the procedure and wing it. Up to that point I feel I have a duty of care to follow a pre-calculated safe path and not experiment with something that may have unforeseen consequences, even though done with the best of intentions...