Weir had her own skillset that no one else really filled
Yes, she did. Unfortunately, it just seemed like the writers didn’t really know what to do with the character and her particular skillset. So instead of developing the character they simply replaced her.

The more I’m talking about it, the more I realise I’ll probably be just as annoyed about certain choices TPTB made for the show as I was the first time around. *lol*