I always envisioned Nicci as a tall, blue-eyed,blonde ice queen.

I guess the casting directors realized that they'd had a string of really delicious tall, blue-eyed blonde ice-queens on the show, and wanted to shake things up, lol.

But I think I'll be able to get used to it ;)

Of course you will! It's fucking T'Pol for christsake! Of course you'll get used to it, and you'll like it! lol