A 115mm f/1.4 would be a monster of a lens - big and heavy. Tamron has definitely proved itself worthy in my opinion after purchasing the 45mm and 85mm lenses in their new SP line. I'm not sure if Tamron is ready to tackle such wide apertures just yet. I'd like to see them produce something in the mid-telephoto range either a 115 or 135, and I'd be happy with 1.8 to keep the size/weight reasonable so long as the lens had VC. After all Canon's 135mm lens is f/2 and while sharp it is showing it's age and could use a refresh. I own a copy of the Canon lens, but if Tamron produced something and released it in 2017 I'd probably jump on it with the certainty than a new Canon lens will beyond doubt be more expensive.
I'd also like to see a wide angle offering from Tamron too just to keep things interesting. With several bad experiences with Sigma none of their offerings are on my radar.