Thanks for the good pictures, especially the krug, and the comments!
I forgot to add a few infos about that cuirass: the photos are more than a year old, while the cuirass was an absolute side project in the last 2 years. I've drawn the patterns for the plates directly onto the steel free-handedly, and I, indeed, made the armpit too vulnerable. I'm currently planning the next version with more krug-ish lines, but with keeping the "musculata" feeling. Oh, and I didn't know anything about the krug back then... And it was my first-ever m&p stuff. Even then, I'd like to finish it with elbow lenght sleeves.
Tim: I know, you're quite right, but back then, I thought that I'd need such a big armpit for mobility. I was wrong.
The mentioned sleeves'll help a bit, but won't solve the problem fully. The next one will be better for sure.
It seems to me that the eastern people tended to have quite thin arms - I haven't really seen any bazuband that could fit to my arm. This seems strange because they were fighting and shooting arrows most of their lifetime... Or am I wrong?