I don't even have a ranger currently but let me tell you guys this!
The way you've set up the Pet for Artificer is JUST what an actual lifelong (sort of) Animal companion should be. NOT just another summons that dies 3 mins after summoning. Not just a Moments distraction for Mobs.
A True companion that grows and gains strengths with levels just as we do.
I would LOVE to see fresh life breathed into The ranger class by implementing this for them. It is, after all, what their animal companions SHOULD be like after all.
On a side note, something small but similar for familiars would also work for mages...