Have you seen the other topic on this at:
viewtopic.php?f=42&t=30097I can't comment on the Magg 17 track itself, but I took my kids (and my mate took his kids) into the Pelion area (and climbed Doris) via the Arm River Track a few weeks ago, and I was pleasantly surprised at the track work that had been done to make the ascent a lot easier than it used to be. The 6 kids ranged from 9 to 16, and none of them had any problems with it.
There is still a long constant up-hill slog for a while, but instead of going directly up the slope at fairly extreme steepness (is that a word), it now zig-zags up the slope at a more moderate steepness. And the track is very well formed (ie, flat surface as opposed to rough/rugged surface) and it is quite easy to walk on. It's some very impressive track work!
If you look carefully, you can still see where the old track was where each 'zig' or 'zag' crosses its path, and it's a good reminder of just how much easier the upgraded track is.