Essentially broken - both as a mutant and as a person - from the beginning, Summers has had to deal with loss from one situation after another for most of his life. He's lost loved ones, control, and the respect of both fans and the fictional community that he's protected for so long. Throughout the long-running history of the group, his loyalty, support, and intelligence have made him an invaluable member of the X-Men, as well as an excellent leader (despite that one time Storm beat him in a fight for leadership of the X-Men). And this all happened before his villainous turn, going from the milquetoast Scott "Slim" Summers to the militant mutant leader Cyclops, which is the most interesting phase of his life thus far.
All of this, of course, was basically thrown out when it came to the X-Men films. While the militant leader stuff had yet to exist in comics canon by the time the original trilogy of films came out, James Marsden's portrayal of Cyclops was a bit thin to say the least. While not Marsden's fault, the film gave little time to the leader of the team, especially with breakouts like Jackman's Wolverine getting a bit more time to shine. Marsden made an effort, but between him being in love with Jean, being mad at Wolverine for being in love with Jean, and eventually (more spoilers for 2006's X-Men: The Last Stand) being killed by Jean, there wasn't a ton of room for Scott to develop. Now, thanks to this altered timeline that started with X-Men: First Class, Scott Summers will be making his return. Played by Tye Sheridan, this looks to be an introduction to the young Summers, a vulnerable mutant with little control of his powers and even less knowledge of the world.
Hopefully, X-Men: Apocalypse will bring forth a whole new persona for Cyclops, and this time, he'll have something to do, so that he can - after over sixty years - shed the polarizing stigma he's carried with him for so long.