So your choice lies in late 2017.
Right MS killed Slim because gamers are unsure about buy it or wait the Scorpio... MS is not selling consoles.
In Sony case they gamer will buy one or another... they will just choose between one of the options... Sony is selling consoles.
Isn't Sony killing the slim by offering a more powerful console at the same time? Why would anyone that doesn't have one buy a slim if they think they're buying an immediately inferior product?
Doesn't the XB1 slim serve those that don't have one by offering a revised product at a cheaper price and by offering the cheapest 4K player allowing people to get involved in the ecosystem and trade it in or save until the release of the next console? I doubt people will go a year without playing titles they want if they're interested and they're being told that games will work between the two so there isn't as much FOMO.