Umm, could we try to get back to the question here and understand just what it is that people dislike about 'clipping', because I think we may be missing a number of points.
In summary, a 'clipping' assault often relies on winning by using
1) Assault Resolution factors other than casualties to win the resolution.
2) Other forces to 'pin' the defenders preventing them from engaging the attackers.
3) Supports that can fight without being shot at.
IMHO 'Other factors' represent the different states of fomation morale or preparing the assault, and generally most seem to accept the principles here. 'Pinning' part of the target may be a little more controversial, but effectively represents combat between these forces which do not contribute in any other way. Again this would not seem to be too controversial.
As Chroma and others point out, the main 'oddity' seems to be where the supports actually participate in the assault but cannot be hurt in return. Is it this particular element of assaults that is at the heart of the problem being presented?
Support fire has already been toned down in a number of ways by restricting the target of the support fire, and now by requiring the attackers to survive the defender's fire before the supports may participate. Historically these changes were designed to get around this particular aspect of assaults - where a small sacrificial formation is used to bring in the superior firepower of the actual assault.
Perhaps as others suggest, firing from the assaulters, defenders and supports may be allocated to all the participating formations under particualr circumstances. So perhaps firing on the supports must not exceed firing on the attacker/defender etc. Note, even doing this you will still hit oddities through the 'pooling' of hits.
So what else can be done, and more importantly is it worth it?