While the initial panic would be over the perceived notion that the Stars are "getting younger", it's important to remember that the Stars still need scoring depth and help in the short term. A Jagr contract would be for only one season and at the very least, he would create all sorts of interest in the team locally and likely nationally with his presence alone.
Jagr returned to the NHL last season with the Flyers and was overall impressive, scoring 19 goals and putting up 54 points while still showing the skill that made him the most dangerous player in the NHL a decade ago.
I'm not particularly put off by the notion of signing Jagr, only if his presence this season does not hinder the progress and opportunities of the young players on the roster. The Stars need to be competitive and sell tickets, however, and this would be a very big part of that process.