This topic comes up all the time in HEMA. How much safety should you sacrifice in the name of mobility. I have read a number of articles and I have to agree with the general consensus even though it is the least interesting: You need to decide for yourself. For a long time, I have used a linen based fencing jacket with minimal arm protection. Recently, my fencing has increased in intensity as my abilities have improved and I have been coming home with more and more bruises. I have made the leap to a more protective jacket, the SPES Hussar coat. The protection is fantastic, but I sure do miss the mobility I used to have.
Hopefully, things will get better as I break in the coat and get used to the new normal.