I do like the Rune Knight, though I would prefer the Rune's abilities effects be specific to what type of item they were "attached" to (offers a little incentive and flavor to change things up a bit, perhaps allowing the use of the same rune on two items for a more flavorful concept). I mean the versatility as written is nice too...but I suspect would become quite "samey" rather quickly (at least until reaching 3/4 runes known).
The way it currently is, limiting it just to weapons, shield and armor seems kinda/sorta oddly specific (I mean those are certainly common places to see etched runes and such)..."runestone" is a pretty common thing in fantasy gaming too (you're already limited in the number you can imbue...why restrict it yet further?)
Little interest in the Swarmkeeper, since I'm one of those that finds the Ranger remarkably underwhelming in 5e.
The Revived...that just doesn't feel "right" as a class-specific option. That feels a LOT more like it should be a race option.