Rumors about a "Tiger Cub" based on the 675cc motor have been in play for 3 years or so now. Lots of speculation on forums (see various ADV rider threads). Latest rumors suggest two versions, one off road oriented, one more SM or street tour adventure style.
Will either be a good travel adventure bike? We'll have to wait and see, but I have my doubts based on Triumph's most recent model introductions.
I'm glad Triumph has picked up on this current trend. I'm also very glad the Japanese have pretty much stayed mute during this whole phenom that BMW and KTM have fired up. This will give Triumph at least a chance of making this whole effort worth the trouble and cost.
The Adventure bike movement is one of very few still profitable segments in motorcycling. Dual Sport/Adventure may have a future. BMW have managed to turn around their previously unprofitable bike division with the GS1100 starting in the mid 90's. Previous to this BMW's car division wholly supported its weak two wheeled sibling.
By 2000 momentum really began to build for the GS, then came the R1200. By that time KTM got into the mix and things began to get very interesting. Thus far, only Yamaha have introduced a bike labeled as "Adventure" with the new 1200 Tenere'. (In the Giant Trailie class)
In some countries adventure riding has been going on for 50 years ... I guess we just never knew it!

In the UK and EU where NO LAND is available to ride on and going off road will often land you in Jail, this is a relatively new trend. The old timers probably remember a different time before lands were locked up. Did you ever wonder how Husqvarna developed their world beating bikes in the 60's?
But in places like Africa, S. America and the Western USA, we've been doing off road adventure riding for decades. I did my first on a Honda 50 step- through in Mexico in the 1960's. I was about 16.
The original Triumph (Meridan) company were strong and very important in various forms of dirt and street racing around the world. Those in the UK may remember the "Scrambles" events run all over England in the 1950's and 60's. Well documented in the press of the time.
In the USA Triumph were
THE brand you wanted be on. As a teen I longed for a Triumph ... but I could only afford a Spanish Bultaco. In those days Triumph made a 200cc Tiger Cub trail bike (I owned one), a 500cc twin (James Dean rode a Daytona 500 and so did Marlon Brando in the Wild One) and the TR-6 and Bonneville (Steve McQueen rode and raced several in the Mojave desert)
All were raced in the desert, moto cross'd, flat track'd and road raced. A huge influence in the Moto world of those years. (pre-Japanese)
But things change ... lets hope the young engineers at Triumph today have done their homework and understand the market. IMHO, they've screwed up mightily with the Thunderbird and Rocket lll. Wholly misjudging the US market. They will pay big for this. I hope it doesn't sink the company.
This is what happens when you hire NO Americans (in important positions) in their USA Atlanta base of operations. The Brits don't always "get" we funny Americans, never really have. I've met some of the Triumph staff, so this is not here-say but personal experience in the industry.
Triumph have had a decade to study this "Adventure trend" so lets hope they get it right first time out ... because I'm not sure Triumph have the resources to do continuous model upgrades (to "fix" a sub standard bike) the way the Japanese and Germans can.
IMHO, the 675 motor should be a great starting point for an Adventure bike. The Teutonics out there will insist you need MASSIVE Boxer torque to make an adventure bike work. I disagree.
What you need is a light weight bike that handles, can be loaded up
and is tough enough to survive the rigors of thousands of off road (or Bad Road) miles. Its not really rocket science ....
The big four built small CC bikes that fit this bill back in the 70's. Bomb proof do it all "Scramblers" like the CL and XL Hondas (175, 200, 250 and more). I owned a couple.
These bikes were great for exploring the Mojave desert and Baja. In those days all we carried was a ruck sack (worn) and a small tail pack on the rear seat. Funky, inadequate but kids are tough. Biggest problem were flat tires. Tires and tubes today are 1000 times better than the 70's.
So who will be the first to ride RTW on a "new" Triumph Adventure bike?