I don't understand how this can be seen as a replacement for the XTerra 705. They were far cheaper and aimed at the lower to mid budget people and the Minelab brand. When I was looking at my first machine many people said Minelab were best, and I could have stretched to a 705 and looked at it.
The 705 was never going to challenge the Deus, whereas the Equinox 800 does. The idea is convincing people that if they can't afford a Deus, they can have all the benefits and more, for less money. Wireless, light, multi frequency, software updates, gold prospecting and 40khz, so I see this as an attempt to undercut the Deus if your not going for FBS machines.
I suppose the Equinox 600 may fill the 705 slot, but the real flagship here is the higher end machine and I think that's the one that Minelab hope will sell to people with a decent bit of cash to spend who want Deus performance without having to spend as much money. I think it's pretty clear what the target is here.