It is such a big deal that there should be consequences for those who do it. People commit perjury in courts all across the country on probably a daily basis--very little happens as a result.
If this county has to have death penalty then we need to fix some things, and fast. I have no problem with starting with consequences for jurors who knowingly and willfully do the wrong thing. I would never want this case (and many others for that matter) to go as far as being thrown out and Arias have to be retried all over again but I would have no problems with the problem juror being made to answer for her actions.
A logical and immediate remedy to this particular situation would be to switch to a majority vote for determining sentence. It is in place in at least one other jurisdiction and apparently hasn't been successfully challenged. This would be a first step to introducing fairness into the DP, but it leaves the reality of the DP as a contradiction in terms untouched, as well as its many other contradictions, but it is a correct and reasonable first step, imo.
And had, say, a 9-3 majority been in place during the first trial this probably would have been over then, since apparently three jurors changed their minds partly because only one had the singular ability to hang.
ETA: the italicized