I think we do have a fairly solid core of hitters. All of them are at least average if not better except CF and 3B and we have prospects that might fill those spots.
Our problem really is starting pitching, relievers and injuries. We really only have 1 starting pitcher and a few relievers that are solid. Arrieta is worthy of a roster spot, but that is about it. We almost need a complete redo of much of the pitching staff and unfortunately we are completely lacking in near term replacements in our minor leagues. Velasquez, Pivetta and Eflin might be solid starters someday, but they arent today and are not making any progress at all (better coaching needed? Not sure). Vargas and Smyly are just stop gaps, and pretty bad ones at that. If we were smart we would look at adding at least 2 starters this offseason.
Our bullpen is more complex. The guys on the IL would be a reasonable good bullpen I suspect. Some will return, some will not, it is going to be very hard to judge what to do this offseason. 2-3 of Velasquez, Pivetta and Eflin may also get added to our bullpen, which further complicates things. Klentak is going to have a tough job this offseason just judging what moves to make in the pen, frankly, I think this year shows it is better to have more bullpen arms than not enough.
But this biggest issue with this team is that virtually everyone is underachieving. Veterans with years are having seasons at the bottom of their expectations. Young players are doing ok, but not really progressing (except Kingery, Hammer). I think we probably do have a very real issue in coaching. Someone needs to step in and either get Kapler a better staff or get another coach, this just is not working as is.
Franco either needs to move to the bench or be traded, probably the same with Williams. Herrera is going to be a huge headache for this team I suspect, he might be untradeable.
Klentak is going to have a make/break offseason again, he succeeded last offseason (although it doesnt look like it is working out, not really his fault), but the number of issues that MUST be addressed is mounting and taking the trade deadline off (minus Dickerson and some dumpster diving) is not going to help.