Probably has more to do as a compromise with not wanting to instance new shards to handle high pop areas.
This isn’t classic, it’s classic ported to the retail servers. And I suspect the retail servers are a lot more bloated with tasks and sharding is how they load balance it. And we all know how we feel about sharding.
But overall agreed, feels clunky and horrible. Can’t remember if it felt as clunky and horrible in vanilla but my guess it it feels about as bad as BG’s and raids did in vanilla but worse when out doing solo questing.