I was kinda excited about the possibility to apply all available enchants to the heirloom gear. But after seeing the spreadsheet, I'm a bit disappointed. It seems that the enchants don't scale with each level like the stats on the heirloom gear, but instead they're updated at levels 60, 70, 80 and 85. So, if say, you enchant your 2h weapon with 130 agility, it will be scaled to 20 agility till level 60, 26 at 61-70, and so on. Also, the old level 60 enchants are not downscaled, so a 30 spellpower weapon enchant will still give 30 spellpower at all levels. It's a lot less complex system than I expected, but at least we can enchant the shoulders and legs as well.
I can't post links yet, so I hope someone else can post the link to the spreadsheet for me, it's not hard to find. It's from the PTR, but I believe it works the same on live.