The manager at your local GW probably knows less about what's coming up than you do. It's rare the company tells them anything before one of the reliable rumour mongers has already told us, hell it's rare they tell them anything at all more than a couple of weeks in advance.
While the scale change is I'm sure somewhat galling for people with really large collections, I don't know that it will be as dramatic as some fear, the scale for Epic models was already all over the joint. I'm more concerned about the prices - if we are getting FW resin and they keep their pricing relatively consistent, in 8mm scale you're looking at roughly Castellax > Leviathan > plastic Knight in terms of a Warhound > Reaver > nuWarlord progression(they'd be slightly smaller in each case, but those are probably the closest). That's £30-ish quid for a Warhound, £70-ish quid for a Reaver, and something like £120 for a Warlord. Knights, if they get to them, would probably be Thallax-ish, so £30 for three.
Even a small game-ready force at those prices is going to be extortionate, and woe betide the poor buggers who have to buy two forces to try and build some playerbase in their local area. I'd love an AT demi-Legio or even just a modest battlegroup, but modern FW rates price me right out and I'd wager I'm not alone even among the kind of crusty old vets GW likely expect to support this SG rerelease.