Registering various kinds of blocks in Minecraft
Your updated version is pretty darn good.  As in, "You're basically done, no need to make any further changes." (See note at the bottom).

The only thing I did differently (aside from creating non-normal registration methods as well that do all sorts of things) was to take two classes I already had and give them the register function: ClientProxy and CommonProxy.

My setup is such that ClientProxy.register calls super (which calls GameRegistry.register for the block as well as creating and registering the itemblock) and then calls ModelLoader.setCustomModelResourceLocation for the item (or registerItemVariants for block-variant items, or other methods for other pathways).

I later moved this code over into a library package I already had (centralizing the gains and avoiding duplication), added some static methods (in the Common) as helper redirects and ended up with this class which can be boiled down to these two methods for the basic no-nonsense blocks:

public void _registerBlockWithItem(Block block, String registryname) {
    super._registerBlockWithItem(block, registryname);
    _registerBlockResources(block);
}

private void _registerBlockResources(Block block) {
    Item item = Item.getItemFromBlock(block);
    ModelLoader.setCustomModelResourceLocation(item, 0, new ModelResourceLocation(block.getRegistryName(),"normal"));
}


The first method being equivalent to your register method which self-calls your registerClient only on the client side, which then allows us to merge init and initClient.

This made my ModBlocks (well, main mod class in my case) very slim when it comes to registering blocks and items. Looks almost 1.7ish!

There are still some minor improvements which could be made, but at two-three lines per block it's a vast improvement over your original thirteen lines per block.

Note: you should also mark registerClient as @SideOnly(Side.CLIENT) as well: that method is still refers to a class that doesn't exist on the server (ModelLoader) and may crash the dedicated server when the JVM tries to load your ModBlocks class.