I've been lowering the OGs on some of my favorite beers. I've found that in addition to reducing the basemalt, I've reduced the specialty malts to keep the %s the same. So, it still stays 90% two row, 5% crystal, 5% Munich malt, for example.
Then I scale the hops so the IBU/SG ratio is roughly the same.
I do this because sometimes I have a beer that I love, but the ABV is just too high so I try to lower it. Sometimes it works great, sometimes it's less great. An IPA is really tough- you want big hop flavor and aroma, but need enough malt to back it up. I finally got my favorite IPA recipe down to under 6%, and I'm still happy with it.