My research has lead to be believe there are two issues that both contribute to the splay:
The first was the change from 1.6mm to 2.3mm hoops
The second, is attributed to the theory that the actual shell is now ever so slightly smaller than they used to be. The evidence used to support this theory is that the specs of Imperial lug itself haven't changed, yet there is a distinctly larger gap between the centre bead of the shell and the Imperial lug on newer drums, especially when compared to those of the 60's and 70's. The best explaination for this discrepancy is that the shells (no doubt as a cost saving measure) are now ever so slightly slightly smaller.
It's worth noting that I haven't been able to confirm this through any official sources. But it makes sense and all seems to fit. The theory is touted around the internet in various places if anyone cares to look for it. Given this, I'm gonna hazzard a guess that it won't matter what 2.3mm hoop you use. The smaller shell is still gonna come into play.
Originally Posted by bobdadruma
The lug insert is designed to swivel within it's seat in the lug casing to accommodate a certain degree of tension rod splay.
It doesn't cause any tuning issues or damage to the drum.
Most definitely. It's an aesthetic issue only.....hell, even Cindy crawford had a mole on her lip. I never heard many complaints there. ;-)