the uchiha clan is not weak without sharingan. they have very good bodies and are all strong fighters with or without sharingan. both orochimaru and jiraiya are past their prime jiraiya is in his 50's and well orochimaru just got a random body right now, we dont really know how much he can do in this new body. itachi hasnt reached his prime yet and is still as strong as jiraiya and orochimaru. so if he isnt the strongest he will be in a time span of 5-10 years.

and btw what aout kimimaro is a mutation? its called a bloodline in naruto. and kabuto hasnt shown any signs of having a demon, i dont think he would have lost to naruto if he had a demon.