From what I've read I would agree they mirror each other.
But the end-of-times beliefs between Shiite and Sunni are different yes? Many Shiites believe the Mahdi will return to earth one day as savior. The Sunni believe something else?
I have stated this elsewhere but it bears repeating here:
Another point where people know little about Islam is that there is a great deal of religious plurality within Islamic thought.
e.g. there are four Madhabs in Islam, which represent four schools of thought, embracing social, political and legal diversity. The dominant one is the Hanafi, but even within the Hanafi, there is a wide variety, from the Wahabis of Saudi Arabia to the Sufis of India. I know very little about the other madhabs but they are out there. To give some perspective the Shias (prominent in Iraq and Iran) form around 6-8% of all Muslims and even they have different sects within them. So viewing the Islamic world as one large mass of people is inconsistent with the range of beliefs within the religion.
What makes Islam appear as one belief is the fact that except for some newly arisen taqfiri sects (like the Wahabis), who insist that anyone not following their way are not "true" Muslims, there has never been any argument within Islam about the "right" way to follow it. On the assumption that all humans have limited understanding and knowledge and cannot decide what is the right way, all ways of following Islam have been given equal status and left to the individual community. Even the Sunni-Shia divide, largely political in nature, was eliminated when the al-Azhar university (teh premier Islamic studies university in the world) recognised that Shite Islam and Sunni Islam are all under one God and included it in the university syllabus.
This has had both positive and negative effects. On the positive side, it has allowed for diversity to flourish within the religion and live side by side and made it easy for people to move within the religion from one kind of thinking to another, this has also helped the religion to adapt.
The negative point here is that since there is no agreement on what is the right way to do it, people have adopted extreme interpretations (like Abdul Wahab, who decided a hundred years ago that all women should wear black from tip to toe) and were backed by inscrupulous leaders who exploited these changes (Wahab would be just a blip in the history books without Saud).
So yes, there have been plenty of discussions, plenty of Fiqh is out there, lots of Islamic thought from the very conservative to the very liberal. What we do not have is a central authority to say, this is right, or this is wrong. This has unfortunately become the purview of politicians. So you have Ataturk banning the hijab in Turkey, Saud enforcing it in KSA, and both are neither right nor wrong.
So to answer your question, there is no Sunni belief or Shia belief. Not all Sunnis share one belief, not all Shias share one belief.
But yes, in general, there is some belief in a Mahdi etc which the ithna' ashara believe in.
For me, this is a deal breaker
The concept of Mahdi is not explicitly mentioned in the Qu'ran, but there are many hadith (traditional sayings of Muhammad) on the Mahdi.
I don't get excited about stuff that is not mentioned in the Quran.