I would say yes, but a lineup of (let's assume Tim retires - if he doesn't, that is a nice bonus):
Pau
LMA
Kawhi
DG
TP
That team, anchored by Kawhi/DG/LMA is still a good defensive team. People keep lamenting the lack of big man perimeter defense, but Tim even when healthy last year was horrible there too. Nothing changes there and despite haven LMA/Tim, SA's defense was unreal good with that flaw.
As long as Pau can protect the rim (which I think he can do good enough) - I think the defense remains very solid. Even if it regresses some due to the gap in Tim's low block defense and Pau's SA could still have the leagues best defense or top 3.
But having Pau in there instead of Tim on offense would obviously help. Pau can still shoot effectively, is just as good of a passer as Tim and is a better low post player at this stage too. The offense should improve well IMO. Not GS level, but very solid.
Then a bench of:
Mills/Manu/Kyle/Simmons/LJC/Murray is not great, but we have to see if Bertans gets fit in along with another big signing on (maybe even West comes back, but who knows). Bench is in a tough spot regardless at the moment.