I suspect this will be drummed out of consideration for racing as soon as it goes into a wind tunnel.
If claims are being made of -16w (and more) going from 46->42cm drop bars I can’t imagine having an extra 150mm of bar/arm/controls sticking straight out into the wind is going to be a benefit.
Flat bars seem to have a moderate cheering section for hypothetical gravel use but few seem to be interested in actually using them. To say nothing of chainring/gearing issues and limitations inherent in using an MTB.
More pics and video of the other two models: https://www.pianetamountainbike.it/tecnica/45728-eurobike-2017-8/70765-scott-2025-a-eurobike
– We’re gonna slacken the headtube!
– Interesting.
– And we’ll give you clearance for mtb tires!
– Wow! I’m in!
– And then we’ll put a flatbar on it!
– You guys should’ve stopped earlier.
next thing you know they’ll bring back the FD
triple chainring 
I definitely think boost is going to come to gravel before long. It really makes a lot more sense than the “wide” cranksets & FDs. Why push the chainine out when the cassette is staying in the same place? In my opinion, the chainline when riding 1x in the lowest gear is totally unacceptable. The same goes for 55mm chainline MTB cranks. WHY? WHY?? 
I love seeing companies like Salsa pushing for this early with creative solutions like using a RaceFace crank with Easton chainrings to get a decent 2x boost setup for gravel. It’s people like them that aren’t afraid to push for the right solution from the get-go rather than putting a different and less efficient standard in place that will inevitably disappear down the road. Gravel does not need its own standard. 
My prediction is that the “all-road” bikes that can clear up to 40c will remain 68mm & 142mm (there’s no need for boost or “wide” setups there) and all of the more capable gravel bikes will ditch the “wide” stuff for boost before too long.
The good news is that we’ll all need to buy new bikes then (unless you own a Cutthroat). 
Actual question: Would Boost increase tire clearance beyond what you already get with Wide cranks? Or would it simply improve chain line slightly in the lowest gears?
Wide cranks move the chain line outboard 2.5mm I think, Boost does so 3mm. Of course you could make Boost-Wide cranks (i.e. even wider than current) but then you’d be back to the same non-optimal chain line, plus Q factor starts to get a bit high.
I think there’s an identity crisis brewing too: gravel gets split into racy road-ish bikes and explorey/bikepacking MTB-ish bikes, but we’re now seeing races won on MTB-lite tires. Will we now see explicitly race-focused/aero gravel bikes build to fit 50mm+ tires? Wheels and tires in this size that try to be somewhat aero (already happening, sort of.) If all this comes to pass, what kind of drivetrain and hubs will the market want on such bikes, especially given that riders of these bikes tend to also ride on the road and might want some cross-compatibility?
Boost would increase tire clearance since it is a standard that affects both the BB and rear hub whereas the “wide” setups are just slightly bumped-out chainrings and front derailleurs. The “wide” setups and 55mm cranks for MTBs are essentially just trying to keep the chain away from the tire when you’re higher up in the cassette. Since Boost is wider all around, there is more clearance in the frame and around the chain.
Since standard Boost setups were developed as a whole system (BB, crank, rear hub/axle spacing) the chainline is a lot better. Throwing the 55mm Boost cranks essentially does what the “wide” gravel does though by further pushing out the chainrings without being able to adjust the rear hub/cassette.
This is why, in my opinion, regular non-wide cranks with 142mm rear hubs and 52mm cranks with Boost rear hubs will always work better than the “wide” and 55mm counterparts…
Road “wide” set ups just caught up the chainline when disc brakes put 135 hubs on formerly 130mm road frames. In other words, there was never a 137mm “road disc TA” standard, they just leapfrogged to 142.
With 2x drivetrains it’s not as much of an issue, but with so many 1x gravel bikes and MTBs, I find it less than desirable.
More recent info about the Scott Scale Gravel.
Those bikes have existed for years 
3T’s Exploro and Exploro Ultra come to mind.
SRAM already has the answer: they have one drop bar group set with a whole host of 1x and 2x gearing options. In addition to full compatibility to mountain bike rear derailleurs and cassettes.
I think that’s much better than Shimano’s solution that tries to push GRX. I see no advantage, just a further unnecessary split of your product lines. Instead IMHO Shimano should have made their drop bar components compatible with road and mountain bike components.
My next commuter will be something like that: a fast flat bar bike with gravel bike gearing.
I’m there!
With a rigid fork, this thing has a 74mm BB drop and a 69.9-degree HTA.
The SQ Labs Innerbarends work really well for faster cruising, and honestly, I rarely need anything more than a 34x10 around here, but there is room for at least a 38 if I ever feel I need it.
I’ve got a Fox factory fork that I can swap in and another seatpost with a saddle installed that’s adjusted for the change in geometry so this bike is really, really, versatile.
These only clear fat tires in 650 size. I own an Exploro Racemax (the current version with extended chain stays) and it can clear some but not all 45mm tires with pretty limited space for mud or debris. Circumference is the main limiter.
I’m thinking something like a Lauf Seigla, but aero. Clearance for mega tires and racy geometry (check) but the Seigla is pretty aggressively non-aero; the downtube is a triangle with the flat side facing forward…
Isn’t there a point though where tire size is going to lean you towards a 650 instead of a 700 because of diameter, regardless of clearance for the width?
Why would it go smaller? bigger is faster?
Why does wheel size (650b vs. 700c) matter? The circumference-as-measured has to be within a certain range so that you can fit narrower tires on a 700c wheel without changing the geometry too much.
My hardtail is on commuter duty as my new home doesn’t have mountains and hence, no mountain biking. I’d love something taller than a 34-tooth chain ring. I could fit a round 36-tooth chain ring (I use a 34-tooth oval chain ring at the moment). Even with the Schwalbe Racing Ray/Racing Ralph combo, I get to 33–35 km/h very easily, faster in some portions.
34x10 on 2.4" tires at 100rpm is ~30mph which I’ll hit on the backside of the rollers around here, but I’m not pushing that type of speed for long on the flats.
I’ve hung onto some group rides on the road with this with no issues. We’re not averaging 29mph over here. 
Not quite, but since this is mountain bike gearing, there is a larger jump between 34:13 and 34:11. I’d like to add a chain ring to push the most used gears one or two gears down.
ahh. I’m happy to use the 10t every now and then with a smaller chainring since it gives me a lower gear at the other end.
I’ve had too many bikes in the past where the 10/11t cogs almost never get used. I’ve found in those cases I’m better off with a smaller chainring so that I can dip into those smaller cogs when I need them.
I’m not mashing the small downhills around here for more than a few seconds, so spinning out in the low ~30mph range doesn’t bother me.