I think new audiences probably wouldn't care either way. But old timers would enjoy seeing a tie in from the old universe. Sort of like a nod to them.
Spock prime was totally unnecessary in the second film, but I thought he worked well in the first one.
Would have been interesting to have Shatner in the second movie as something. Maybe Kirk's grandfather? Heck I don't know? I would have appreciated it.
Agree on all thoughts here.