Called Shot
It's not that effective as Kai or Rage, so I guess it may be allowed at 1st level.
+1 crit chance, hmm. Kit indeed isn't weak, but it progresses in levels at a slower pace than kensai; later in game it's generally melee that pwns people, not shooting; and kensai can have both damage bonus and extra crit bonus from weapon styles. All together, it probably can justify that +1.
Stalker
1, 3, 4 - indeed. 2 - has a logic, but imo goes to being too close to F/T.
No clues about new features, though...
Basic class has it's own bit, so yes. I support the idea too.