As a merc-packing man I agree with your posts. There's actually some things wrong with mercs from obvious bugs to lack of control options.
Gotta agree with parts 1,2 and 3.
Before number 2 can be included, the mentats-exploit must be solved.
Regarding 3, you can always punch your merc and run for the stuff when it's on the grid. On the other hand stuff on the grid could be also considered as "lost" stuff, it's there but no one can reach it. Think of yourself as a kid starting through the window of candy shop and you got no pocket money. This is just speculation but it would totally make sense that merc could pick the stuff up but then again why can't players?