OC defence for ZZ does make a significant change.
Defence up + OC defence allows you to tank really good, however you have to trade off the extra attack you can get from OC for defence.
Still, I see people prefer C speed OC attack for ZZ (A) not sure why, I feel the speed is sufficient. I mean take a look, use MA mode to travel, change to MS and melee to catch people ... voila. Also, newtype awakening gives you more than enough boost and speed. So, I'd go for C hp OC attack/defence for ZZ.
For Raider, its really up to your playstyle. Some people prefer a raider that can tank and maximize the use of W3. I however, prefer to use W2 as my main weapon ... you simply cant say no to badass zooks on steroids.