Depends on the direction our manager wants to take us.
It starts with how many strikers we want to start in most games, if we want to start two then both Ade and Soldado could be kept around. I really feel we have to rethink our central midfield if that's the case though. I'm not sure about Paulinho, Capoue, Bentaleb (at this point) or possibly even Sandro and Dembele in a 4-4-2-esque formation. They all range from good to excellent, but the only real proper passer in there is Bentaleb and I'm not sure he's ready to be first choice in a system like that. We're really lacking balance in central midfield if we want to move in that direction.
If we want to start with a lone striker for most games then I think we need to have a "complete striker" as our first choice striking option. Someone with a bit of height, strength, pace, skill, finishing ability etc. If you look at most top teams regularly playing a lone striker they have one of those strikers available to them or as first choice. The exceptions are teams that are so outrageously good on the ball that they don't need a physical option/holdup player. I'm not holding my breath for us to join that category next season. Look at Arsenal with Giroud and the young Sanogo, Bayern, Dortmund, City (under Mancini), Chelsea at their best had Drogba, and so on. I'm sure there are exceptions, but for where we want to move, I think we need that complete forward.
That, unfortunately, doesn't leave Soldado as a good first choice option. It leaves Ade as a good option, but one many of us will struggle to trust as that first choice striker and like Milo says we might want to cash in anyway.
I started a "which complete strikers could we get" thread in the transfer rumour thread this summer (iirc), and also this January. I still think that's a vital question for us if we want to push on.
Mandzukic or Lukaku would be up there on the wishlist, but probably both are like wishing for a supermodel from Santa for Christmas.