I'm thinking Triumph can solve the ground clearance issue in two ways:

1. Suspension
By adding travel, ground clearance will be increased. It's likely one of the models may use a 21" or 19" wheel. This too will raise ground clearance a bit. I'm hoping Triumph give this bike at least 10" of travel. A heavy-ish bike needs long travel to work off road. My DR650 single has 8" of travel and is STILL the lowest stock dual sport single in production.

2. Rather than move the motor UP, Triumph could do what the most innovative off road bike manufacturers are now doing: Tipping the motor either forward (a la Husaberg) or back (a la the new Yamaha YZ450F)

Husaberg and Yamaha did this for handling reasons, shifting COG and mass centralization. Also, keep in mind, raising the COG really lightens up the handling feel of a bike. A low COG means slow but stable handling. In the last ten years race and sport bikes have all raised up the motors and the COG to quicken/lighten handling. This true with off road bikes as well.

If Triumph simply build a Faux off road Adventure bike, suitable only for the Cafe circuit, them none of this matters. If they desire to make a true "do-it-all" travel bike, then other problems must be addressed.

The 675 motor is ideal due to it's super light weight and small size. It's much smaller and lighter than either the F800GS or DL650 Vstrom motor.
In fact, it probably weighs less than my DR650 motor, now a 14 year old design.