This seems like a nice class for high powered games. But you may wish to tread carefully if you are trying to keep player power appropriate for released premade modules (without needing significant encounter tweaking).
The Crimson Rite damage easily competes with Barbarian Rage damage and is easier to maintain (for a fairly nominal hp cost - plus he gets combat styles). The Blood Curses, while not quite as good as a Battlemaster, is close to that in utility. These two features along with other base class features make a fairly viable character WITHOUT the subclass features. He functions well at range or melee. His range capability goes a long way in lessening the impact of the HP cost of his abilities. The subclasses then ratchet up the power and utility of this class to places that may be problematic.
A key here is that very few of the class features are aimed at social or exploration pillars. This guy is almost 100% combat and it shows.
If you are going for a powerful game full of feats, multiclassing, third party stuff and homebrew, this will be fine. Just make sure that other players are using character options that approximate this thing's power and utility. As a DM, you will probably need to tweak (on the fly) planned encounters to challenge the players and you may not find premade encounters up to the task. However, if you are running a high powered game, you know this already.
This isn't something I would allow unless I am running a game with very few (like 2) players since this is almost like a 3.5E Gestalt class. However, it has other uses. I have used the presented features to craft classes that I am more comfortable with and to fuel my imagination in crafting interesting NPCs.
In short, it has its uses but it isnt for everyone.
PS: If you do wish to allow this class and want to keep the power down slightly, here is a bandaid fix: only allow Crimson Rite damage once on your turn. This is still a bit powerful but it won't constantly outshine others.