I have had no concerns with mine and think the two "issues" you mention are a little over blown.
I would not call the battery door "flimsy". While not as robust as the doors on the DSLR models, it is solid and snaps firmly and securely in place.
The "give" on the grip I believe is simply a matter of a molded plastic piece that doesn't have .000 tolerance to the surface it is mounted too. If you squeeze harder than ever necessary on the grip, you will notice a slight give. I had my M5 for about a month before I heard of the issue and had not ever noticed it. Once I read Bantu it, I went and squeezed my grip and sure enough felt the ever so slight give under pressure.
Unless you really ham fist it, I doubt you would be aware of it without have read of it.
Totally agree ......