Technically, the Order of the Dragon ability doesn't modify the bonus that Aid Another grants, it adds to it. I've seen most DM's allow it to work that way, though I can understand concern. I'm currently playing a character built around Aid Another, and I was pointed to the Ring of Tactical Precision. That plus Gloves of Arcane Striking is about as good as it gets... unless you can grab the Harrying Partners teamwork feat to share with Tactician, because the only thing better than giving your ally a +8 to hit, is giving him a +8 to hit on ALL of his attacks.
The Order of the Dragon Aid Allies says "whenever an order of the dragon cavalier uses the aid another action to assist one of his allies, the ally receives a +3 bonus" (emphasis mine)
Helpful says "Whenever you successfully perform an aid another action, you grant your ally a +4 bonus" (emphasis mine)
Now, you can probably convince your GM to let them stack, but as written, they don't.
I do love the Harrying Partners feat: my Helpful Halfling cavalier is picking up that one next, and my Brawler/Holy Tactician paladin has that one her go-to list to learn as a move action (along with Outflank, Paired Opportunists, and Swap Places).
The best use I've seen for the Ring of Tactical Precision is the two characters in our area who used them as their in-character wedding rings: they each bought one, took different teamwork feats and then trade rings.