Yeah nah, I've heard people say various places in Hornsby need to be widened or something, but I completely disagree. Hornsby is one of the wider trails around, there are hardly any trees that are close to the trail and get struck (you can see damage on the trunk in such cases). Obviously this is because of the nature of the trail, being a popular one for riders of all skill levels. But it doesn't need to be made any wider.
Lots of trails around are tighter to trees, and I think its a good thing. Trails that you would have real trouble fitting a 800 mm bar through are some of my favourite. Kentlyn is a good example, in particular the "No Fat Guys" section. Close trees make hitting the ideal line a bit more of a fun challenge.
Some of the dirt sections of the Stage 2 black trail have ideal lines that are really close to the cut away hillside, but before these lines got ripped up by use, they were actually really nice and riding so close to the cuttings at speed was a rush. The tightness teaches you to be really aware of where you handlebar ends and pedals (and shoulders and knees) are.