This posting is more a question to the experts rather than a real feature proposal. In fact I don't think this feature is very important and would prefer to see other things improved.
In several battles, corps or even army commanders have directly taken the lead of a unit in a decisive attack. Take as an example Ney leading the cavalry charges at Waterloo, almost being killed (if I'm not in error his horse was shot).
So, do you think that these instances justify the introduction of a mechanism whereby a senior commander can be directly attached to a unit, therefore increasing its morale. The trade-off would be of course that while attached in this way the general would have his command ability heavily hampered, and he would have a greater risk of being killed/wounded or captured.
Regards,
António