It is hard for me to see clearly how the Celtics are going to fix anything or balance their roster better with what is likely to be available via buyouts. I see the ideal core line up as follows:
Kemba, Brown, Tatum, PF, Center
with a bench now that would include Fournier, Smart, Pritchard, Langford, Nesmith, and whatever bigs (PF, C) that don't start.
For Center, I am fine to start either Thompson or RWilliams, either can be part of the core whether they start or not. I expect similar minutes. I believe that Drummond would be an improvement over either of these and would help. It would have to take minutes away from one of Thompson or RWilliams but if it made the team better, so be it. I am not so sure that Dieng helps much.
The big issue remains PF. We came out of the trades actually worse off if you consider that Theis was playing a lot of minutes at PF. If nothing changes, we can approach this one of two ways, play one of Wagner, Ojeleye, or GWilliams as a starter/core rotation PF or we can play without a PF. I don't think any of the PF options are good enough to play regular rotation minutes so I don't see that. We could do the PF by committee approach and share the minutes based on match ups but that still isn't great either. I don't think getting Otto Porter helps much with this as he is more wing than PF and we already have options for that if we want to go that route. Kelly Olynyk is not really a starting caliber PF either.
That leaves us to play without a PF, like we did all last season. To me, that means inserting either Smart or Fournier into the starting/core line up. It will likely be Smart as he is the most versatile and Fournier still needs to acclimate which is easier to do coming off the bench (but still seeing starter minutes). Not ideal to me but in terms of buyouts, I don't see any viable options to address this issue. Fournier and Smart are both much better options than say Porter. Porter's role would be what we would otherwise get from some combination of Langford, Nesmith and say Ojeleye. Doesn't seem worth it to even bother with Porter.