When spinning reels first came into this country the spools were quite large in diameter and short fore/aft.  Remember the Airex?  From France, I think.

Then, as an improvement in casting, they changed to have smaller diameter spools that were longer fore/aft.  Most reels today are of that configuration.

But, as an improvement to casting, some makers are now making their spools larger in diameter and shorter fore/aft.  The new BPS reels and a couple others look just like the old Airex reels my dad bought back in the late 40's or early 50's.

Interestingly, the line he had was braided, as mono didn't exist.

I haven't tried the new reels, but I expect they handle flourocarbon and other stiffer lines better.

I can't tell any difference in casting distinct BUT I do believe it cuts down on loops and line twist.....especially wind knots. Having less coils coming off the spool makes the line perform a little better.... Atleast that's my experience.

Yes I noticed it too.  I think it's just another way to sell you something.  My dad looks in the bass pro catalog with me every so often and sees a lure advertised as "new" and says he used to fish with stuff just like it when he was a kid.  Then this year they actually have a Strike King tri-winged buzzbait advertised as new but I've fished with them for 12 years now.  Might be new to them selling it but I highly doubt it.  All in all, it's whatever they can do to get your money, pure and simple.  Put out a spinning reel design and let it run long enough that it's flaws are well known, then change the design and bill it as new and improved and everyone will go to it.  Run it for so long that everyone forgets about the old ways and also all of it's flaws are well known about too.  Then change back to the original design and suck in a few new people who never fished with the first one.   ::)That's my take on the whole situation.  I say pick what you like, fish with it, and forget all the "new and improved" or "casts better" stuff.