I'm not really in a position to do a review,but here's my thoughts on the route.
Firstly,for me it's a great route,98 miles is no easy task,add to that areas that are not well covered by google/photographers,and the fact that the route is also set 30+ years ago mean that finding resources and putting them to work is not something to be envied,that I can assure anyone who questions it.
With regards to the track,it's pretty much spot on,gradients seem bang on from what I've seen,trackwork is also neat etc.
The signalling and speed limits also seem accurate.
Regarding the scenery itself,whilst the route is very well portrayed and is 100% a good representation (which makes it more than good enough for me),I do think that some work could've been put into scaling trees,as currently all the trees are the same size,not a major issue,but it's one of those little things that I think could've added to the route even more. My only real concern is the scenery in some fields (Leaving Crianlarich towards Tyndrum Upper is my prime example so far),it's a little bland,some shrubs/bushes/animals could've really added to some sections,even if it were just grass laid on the valley floor.
I know how hard the Highland sections are to add scenery to (I found that when I did Kyle) but I would question the use of gorse bushes around Rannoch and Corrour,that does seem a little bit out of place to be (brutally) honest,maybe some bracken/grass would've been a better idea,but again it's a very hard area to add scenery to,not much you can add when there's not really anything there in reality!
My thoughts on people saying the route should've gone to Glasgow,now I'm speaking from a personal point of view here (I don't know the situation surrounding DTG/Milepost addons) but I simply couldn't pitch to build the WHL with Glasgow if I were trying to make it,to do the Helensburgh-Glasgow section (for me) would take at least 3-5 months,3-5 months that may mean the dev's would've had to wait longer to make any earnings on their hard work. Also time constraints may come into it,there may be no pressure on a freeware dev to release a route (I can't think of a situation where there would be),but if you're running a commercial project you have to draw the line somewhere if you ever want to make a profit,I can imagine that completing the route to Glasgow would've cost someone a lot more money,and then there's all the assets that would've needed building (and paying for) on top of that.
Note: The last paragraph is pure speculation (like most things on forums

).
Overall a great route and representation in my eyes,speaking from a personal point of view.
Cheers,
Mark