I've been very curious about the star also. I think it looks great above the crest and in my opinion I think it is something we should keep on all the jerseys because of how incredibly special being crowned European champions is to the club. I've been reading that Italian teams do this, German teams do that but in the end stars are symbolic to the club and there are no rules or regulations that says one team can or cannot put a star anywhere.
The star, if kept, will forever remind me of the utterly incredible European campaign Chelsea had in 2012 and when the great players of our club had their backs against the wall on numerous occasions and had to stare down defeat itself and STILL came out on top. If the comeback against Napoli, the holding off of Benfica, the historic 10 man draw against "the greatest team ever" and a final where we overcame a goal in the 83rd minute to win 4-3 on penalties in Bayern's HOME stadium doesn't warrant a symbolic star...well then, I'm not sure what does. We earned it because the 11 players on the field never lost faith and I think it should be remembered for as long as Chelsea plays football.
A side note too, I just purchased the 12/13 home kit from the megastore with the star and got Drogba's name on the back because despite him moving on, I will always remember what he did for our club by wearing the first jersey he won't be. My way of saying thank you.