For the record, Pre-ex is illegal under any HMO health plan. In 23 years, I have never, ever seen an insurance company even come close to dropping a specific person for just for having medical claims, unless fraud is involved.
The problem is that there is an asymmetry here - between passing legislation and repealing legislation. If you assume a massive shift in party control in the Congress (both houses as the result of the 2010 elections) but not enough to override Presidential vetoes, then repeal of this has to wait for Jan. 20, 2013.