Do I think Logan original script had some ideas that pushed the outer envelope? Maybe. Do I think that's why P&W (associated with 5 films and 15 years with EON) were brought back in? Probably.
Do I think Babs and Mike are going to kill the golden goose? No way.
I think that this is probably where we're at with regards to the state of SPECTRE. I would imagine that bringing in P&W would be a way of getting things back towards a more neutral center, as opposed to the extremes that Logan may have taken things. It doesn't sound like anyone was all that happy with the initial draft that Logan turned in, and they really could have turned to anyone to fix it, but they went back to the well and brought back P&W.
Regardless of what one might think of P&W's writing ability, I think it's pretty clear that they know the Bond character and Fleming's novels quite well. My thought would be that this might be a reverse situation of what we saw with Casino Royale, where Haggis took P&W's more seemingly more faithful take on Fleming's novel (if I recall, they've alluded to this in a few interviews) and took it in a slightly different direction in certain places (most notably the final act at the sinking house). Now, we could be faced with P&W coming in to reign things back into something more in line with something that's more Fleming-inspired, i.e. how the SPECTRE organization works, their motivations, etc.