I think that the question is probably the same as the piece of string one, the perfect knife to one person may not be to another. and location is a major factor as well, I'll explain what i mean;
My particular requirements are for the UK.
A good heavy blade that can take being battened. I usually go for a 4mm think blade as opposed to 2-3mm and about 100-120mm in length
A nice flat grind, that can be easily sharpened in the field (now the flat is not as robust as say a secondary bevel, but my particular need is for a flat)
A full tang (flat, not profiled) with a good stabilised wooden handle, in a coke bottle type profile.
Now this for me works great in terrain very much like the UK. However if I was going to say the Jungle, then a large wide 2mm blade with a secondary bevel would be better (basically a parang tbh)
I the arctic north, a larger heavier blade, maybe 190-225 mm in length, and 4mm think, with a longer thinker handle in a more onion profile and flared pommel and heavy guard to be more comfortable with the use of gloves. a large secondary bevel.
I use a knife on a daily basis for work, but I do go by the ethos of the right tool for the job. for instance i'm more likely to use my SFA for battening than my knife, and a small folding knife for finer jobs.
Anyway what I'm trying to say (badly
) is that take your time, handle different knives, and if possible have a go with them, then talk to your maker, and discuss something that contains all the best bits you found on the knives you used.
Da