First of all, Health! I do not think we are good enough to be missing a major piece and still make it to the finals, not in the stacked East.
Assuming health - The Jays are a great 2 wing combo - the best duo in the East, Brooklyn top 2 may have more skill, but also more health concern (Durant)and head case concern (Kyrie!)
PG with a healthy Kemba (like first half of last year) and FastPP as a back up is playoff caliber. given those 3 top notch positions, I think we can live with our 3 headed center position. 2 are at least league average, and Timelord may be by the end of the year.
The rub is our 3rd wing. If it is Smart, then our bench is weak, and I actually think MS plays better with his energy coming off the bench. To truly be finals ready, one of two things need to happen - either one of our wings needs to take a huge leap during the year. I appreciate the growth in Gwill and Semi, but that is not enough to make the finals. We need a quality two way wing. The one other possibility, is that at least 3 wings take moderate leaps (and this must include the offensive end), and we have 3 almost starter quality wings, out of Gwill, Semi, Jgreen, Nesmith, and Langford and we can mix and match. But I think these are the less likely scenarios.
I think the most likely way we are finals ready, is to use that trade exception, and pick up a quality 2-way wing around the trade deadline. If we feel good enough about our current player's development, this player could even be a 1/2 year rental (reducing the cost in assets).