I've never been one for subtlty in flavor (my cooking has been called "a full frontal assault on the senses" so I'd say go for it.
The most critical thing here is what you're adding from the orange. You want to use a zester, grater, vegetable peeler, etc., and carefully zest the orange so as not to add any of the white part of the peel (pith). For adding the slices properly, again, make sure they're free of pith- possibly remove the skin and put the pulp in loose.
If you have any POTASSIUM carbonate/bicarbonate, add about 3/4 - 1 tsp total to offset the added acidity from the oranges to make your yeast happy.
If you want to post the recipe you plan to use people would gladly give advice. I've made a couple of orange meads and they came out great.