Infusing slates of the altar works just fine, and charging runes make it relatively quick to do by hand, but unless you build some redstone timer stuff with specific intervals on multiple altars for each of the tiers of slate, automation is tedious and ruins the aesthetic.
I envision some sort of special tank/smeltery that takes a blood orb corresponding to the tier of slate you want to create and it could goes straight from stone to the relevant level. consuming all the required sacrifice from the connected LP network of the orbs owner. maybe with some upgrade potential to reduce the total cost (more efficient infusion).
Another benefit to this later game system is that if the LP dries up in the middle of an infusion it doesn't lose progress anymore.
Compatibility with hoppers, only feeding out the finished slates, and redstone toggleable to pause production. Maybe combined with an LP network detector that provides a redstone signal when the connected LP network reaches a certain level (or drops below) could allow for good automation of rune and ritual materials.

Obviously you'd make this an efficiency increase instead of replacing the current method, maybe accessible once you reach a tier 3/4 altar meaning you still have to craft plenty of slates to get the various runes before you can even craft it.

Visually I like the idea of 4 arms suspending the blood orb above the stone, particles collecting into droplets of condensed life essence and dripping onto the stone below. But that's just an idea I had.

Network LP was never meant to achieve direct progress in crafting.

Automation is possible and in fact relatively easy with current methods, albeit the need for creative methods exists unless you utilize add-ons to Blood Magic.
Some weird I-can-do-it-all magical block is neither creative nor challenging.

The whole point of the Blood Altar is to have some sort of balancing that challenges a creative process. You can achieve everything in BM2 by just having a self-sacrifice altar and manual labor. If you want to achieve great things that are capable, you should try multi-altar setups with different methods of Life Essence acquisition. If you do it right, your altar should never run dry nor should the crafting take a long time.

You can even limit the crafted tier by temporarily removing a Blood Rune (with a Piston) and/or utilizing redstone timers.

I'm going to implement more features to make automation easier but I doubt that a single block will ever fully automate crafting for the Blood Altar in plain Blood Magic.

This might just be a difference of opinion then, I wasn't looking for a magic do-it-all block, and yes I've built the multi-altar redstone clock setups. they aren't terribly difficult to construct but they aren't aesthetically pleasing, they can also be done right from the beginning of blood magic so this wouldn't preclude their use. what this does is provide potential to augment the aesthetic by not requiring bulky redstone setups around your altars, reduce your overall used space to just one altar plus your serenity area and various demon devices and rituals. And only is available once you've gone through the tedium of doing so several times already, and only for the most basic of items craft-able in the altar, in my mind you'd still need the altar for most infusions. If you think this defeats the purpose of the mod I can't really convince you otherwise, I just thought maybe making the lower forms of crafting easier as you progress would make the later stages less of a grind and give you opportunities to make other cool new blocks for possible decoration. Thus is my suggestion, If you don't agree no worries :)

Aesthetically pleasing slate automation can be built with an item routing network, zero redstone required.

Nightcaste is correct. Using the routing nodes, you have many capabilities for automation, blood altar included, without the large redstone conrtraptions timing everything. The routing nodes can specify certain numbers of slates to keep in an inventory, handle inserting stone, pulling out slates, and only pull out as many slates of a certain level as are needed, allowin you to fill up a stack of blank from 62 to 64, with 8 slates ins the altar and leave 6 slates to become reinforced.
It is quite a beautiful system, honestly, the routing nodes.