I have a 3.6 Outback and tow a 13 ft scamp. The power is more than adequate, but that isn't all there is to consider.
My trailer weighs just under 2,000 lbs loaded, and I have to use a stowage rack on the back of my Scamp to take some weight
off the tongue. The 3.6 Outbacks do have a 200 lb tongue limit. The other item of note with the outback is the cargo limit. The vehicle can only handle 900 lbs -- 200 on the tongue and lets say 350 in the front seats only leaves 350 lbs for cargo. It is enough for us, but hardly a lot. Final note, all wheel drive is not the best choice for towing. The complicated transmission has to deal with some added strains while towing caused by side forces on the ball.
I owned the 2015 Outback when I got my scamp. I determined I'd be fine with the Scamp 13 but decided against the 16. I am happy so far, but there are limits.