Weighing in on the Partial Cover house-rules; What are your thoughts on this:
Possibly (at risk of over complicating the issue) also including:
It should be a fairly minor benefit - a maximum of +2 range. Cover won't help against melee weapons or enemies who are very close, but it will help avoid being picked off at long range.
The second part would deal with targeting figures who are partially obscured by other figures (whether enemy or friendly). Hiding behind friendly figures would be of limited benefit and shooting at a target that is in melee combat with one of your allies would carry a risk of hitting the wrong one.