I used to really enjoy the "9F from Nellie" type articles in the mags, but times have changed and even if you did such a model it could well look out of place against the modern RTR on the same layout. People quite reasonably want their layouts to look of a piece. BRM and Model Rail both feature kit-building quite regularly, including wagons as potential starters and renumbering and detailing features, if only as a side feature, are there every few months. The thing the internet can't replace, for me, is the scale drawing, but these seem to be less frequent. I remember the wagon drawings every month in the Railway Modeller with particular fondness.
I have scans of thousands of articles reasonably well archived, but my first port of call if I want to see a technique or research some detail is usually this website. On top of that, topics like this one provide the entertainment and stimulus that a good magazine can, plus it takes me off my beaten track, which is good.
I do think t'Interweb has inevitably altered magazine use putting more information and examples out there than there ever was in the past, but I still pick three of them up every month.