What feels most like 4e is the multiclassing system. Otherwise it’s convergent evolution and formatting.
At this point many games have used a level-based bonus to everything rather than individual progressions increasing at different rates. The latter is a big part of what made 3.X so broken at higher levels, so it’s hardly surprising that games designed after 3.X ditched it.
First, let me say that the Arcanist appears to be fairly well balanced by the numbers, that the spell preparation mechanic is a nice compromise between the sorcerer and wizard styles, and Intelligence seems like the correct ability score to use. Now, on to some questions and criticisms.
Mechanical issues: Blood focus is an interesting, but it applies to a lot of class features that weren't written with it in mind.
I completely agree with this. I like the class overall, but wish it had more unique features than its spell preparation method. Blood Focus is used either for a bland minor power-up, or to make the character into sorcerer-light, the diet coke of sorcerers.
While the Arcanist feels a needed mechanical niche, one I've been wanting for D&D/Pathfinder since the Magister in Arcana Evolved, they need more flavor to stand on their own as a class. Replacing Blood Focus with its own thing specific to the arcanist, rather than just making it a watered-down sorcerer bloodline, would help a lot like this.
Even if the bloodline types are kept, making their abilities different for an Arcanist would be helpful, much like the Shaman uses "Spirits" with the same types as Oracle Mysteries, but grants shaman-specific abilities for each of those spirits/mysteries.