The link bracelet is very nice, and while expensive in comparison to the other Apple bands, it's actually pretty reasonable when compared with the Swiss bracelet offerings. The clasp and ease of sizing are unmatched.
As for Apple changing the shape of the watch, I think that the design of the AW is becoming iconic and they probably won't deviate too far from it for the foreseeable future. It could eventually get a little slimmer and may need new bands at that time. No one but Apple knows when that's going to happen.
IMO, if you like the link bracelet, you should go for it.