I love that ghosts and every type basically has become less rare. They basically went from ghosts are super rare phenomenon to eeeh well we all have our ghostsThey’ve had prior regions with a single type specialist missing, no? No reason it couldn’t happen again.
It’s certainly interesting to see how the prevalence of different types has changed over time. Ghost in particular has gone from obnoxiously rare (to the point of the one Kanto Ghost-type expert really being more of a Poison-type expert) to very common, which I’m pretty happy about since I’m realizing it’s probably my favorite type.
I also think the lack of a notable type specialist in a region can make it interesting and fun to do a monotype challenge run with that type - you as the player get to fill that gap! That’s my favorite way to replay Kalos, a Ghost-type team since that’s one of the missing types.