I would imagine Yokomo will address and thus fix the front a-arm issue. Serpent's fairly recently released SRX4 had issues with front a-arms breaking, thus Serpent addressed the issue quickly and released new front a-arms.
As a couple of the very knowledgable gents above advised "to boil the front a arms " which is a proven method to help increase strength and flexibility.
Agree it is disappointing having a-arm issues, however if that is the only issue that the YZ4 presents its quite minor and should be fairly simple for Yok to fix.