Although I'm new at soapmaking (11 months) and I have never used beeswax in my recipes, my notes and readings have the reasons below (some have already been mentioned above) so as not to use it at all.
1) Beeswax has a melting point of 63°C (145°F) so everything in your recipe (oils-lye-additives) must be at this temperature in order for the beeswax not to solidify while mixing.
2) It should not be used over 3% in a recipe as it cuts down the bubbles.
3) Beeswax is a wax and when it meets lye it won't turn into soap. It may add hardness overall but it is something that is not water soluble and it does not act like the rest of the soap does.
If I would like to add hardness property to a soap I would use more palmitic & stearic fatty acids that can be found in high % at Palm, Lard, Tallow and a few % at Shea & Mango butters along with sodium lactate or salt and less water. Note also that with high palmitic and stearic acids in your recipe you also add long lasting property to your soap bar as these acids are less water soluble than any other, so it will make the soap somehow last longer in the shower.
I think that one problem that we, new soapmakers, do is just copying recipes found around the net and we don't understand why some or most of them do not work as we expected.
Thankfully DeeAnna (and others) have made a soaping school here in this forum and teaches us in a manner that this proverb is true: "Give a man a fish and you feed him for a day; teach a man to fish and you feed him for a lifetime."
This is one of the most basic lesson that a soap class should have: http://www.soapmakingforum.com/showpost.php?p=383997&postcount=17