there wouldnt be any benefit from this other than takes longer to get blocked up and in that case your not changing your oil enough and are going to have other problems.
What are you on about, blocked up
no filter should ever get blocked up and the size of them isn't a design factor in them becoming less prone to blocking. The chap's got a few filters from an 04 model that, he wants to know whether they will fit a FZS. I assume because he's got an FZS and wants to use them rather than payout for FZS one's if these will fit.
there is a reason those highly experienced yamaha engineers built it with that size oil filter,
As said from memory the difference between the two filters is a few mm on the O/D and 20mm ish on the length. The filters are located in very different positions. FZS on the oil cooler located front of the engine behind the the lower downtubes, FZ6 on the side of the engine behind the generator. The FZ6 also has less 100ml less oil capacity and runs hotter, hence bigger filter and from memory (so don't quote me) slightly bigger oil cooler.
The length is a factor with the FZS to enable the filter to be fitted/removed while the down tubes are still in place without too much difficulties.
If the FZ6 filters fits FZS, the only issue could be heat transfer with the filter being closer to the downtubes which could get hotter in traffic but again I'd doubt this would have any real effect.