When the last expansion sides were added Richmond won a Grand Final seven years later. While 2010 was no good for Richmond 2011 saw Brandon Ellis come in and 2012 Nick Vlaustin and Kamdyn McIntosh were added from the national drafts. Ellis is the highest picked player to win a Grand Final in the 2011 draft while Vlaustin was the third highest player in the 2012 draft (following Jake Stringer and Jack Macrae).The introduction of Tasmania into the AFL could come at a bad time for Richmond in terms of a rebuild. I think they've got 2 - 3 years of being a competitive mid range team before they bottom out and have to rebuild in several heavily compromised drafts.
While it could go to crap when Tasmania come in I don't think it'll be the death knell for any teams rebuilding when they are added.