I like it, but i can't see it being overly competitive.
Your comment about extra armour on Rhino, just because something is strong enough to kill a Rhino, doesn't mean it won't glance instead, and end up stopping its movement, if you have extra armour, your opponent then has to shoot it again. So it is more than worth it.
A couple of generic comments, that really only you can decide if they are right: Solo Land Raiders aren't that effective. Yes they are still hard to kill, and quite a few armies focus on closer range ways of killing AV14, but against anything spammy like Guard and Wolves your
LR may not survive (although
ML won't be much good against a Demonically possessed
LR) And pairing (or tripling) up Heavy's normally works best, but if you have had success with Vindi and Defiler, you might as well stick with it. Although i'm not too keen on a Vindicator costing 155 points.
As long as the Zerkers make it into combat, you should be able to do more than enough damage to win games, obviously objectives will be an issue, but really you just want to kill the enemy