'Over' is already an adverb. If you want to modify a word with 'over', combine the two words or use a hyphen, as in 'over-concise'. Although 'overly' is now common usage, it is still looked down upon by the literati.
There is nothing wrong with using dashes, but if you do, use the correct dash. The em dash is U+2014. If you cannot type an em dash, the custom is to use two en dashes.
If you care, try switching many of these sentences from passive to active voice. It helps to tighten up your writing. Sometimes it helps for dramatic effect, but excessive use of passive voice slows down your writing. Also, watch your redundancies and overuse of certain words.
There is nothing wrong with using dashes, but if you do, use the correct dash. The em dash is U+2014. If you cannot type an em dash, the custom is to use two en dashes.