The division within Hamas has significant ramifications. There is already significant resistance to certain aspects of the Palestinian unity government proposal brokered in Qatar, primarily focused on the amount of power that Mahmoud Abbas would have, the identity of the unity prime minister and, most significantly, the fact that the Hamas leadership in Gaza wants nothing to do with a unity government. While many news stories have overlooked it, the fact remains that Khaled Mashaal, Hamas' leader in exile, was the primary driving force of the unity deal, while Gaza-based Ismail Haniyeh. There are, of course, more significant issues. Mashaal had spent a decade cultivating ties with Syria, and its benefactor in Iran, but abruptly reversed course and threw his lot in with the Syrian resistance and fled to Qatar. Haniyeh, on the other hand, sees the 800 gorilla, Iran, and has spent significant time expanding Hamas-Iranian ties, including visiting Tehran recently, where he denounced the Qatari brokered unity deal. Mashaal, for his part, has moved to secure support from Egypt's Muslim Brotherhood, seeking some sort of geographic proximity edge (and Sunni counterbalance to Iran's Shia influence), at least in part to compensate for the fact that he does not spend any time in the West Bank or Gaza.
The complexity is more significant. Because Mashaal exercises no functional control over Gaza, his entrance into the unity agreement is largely meaningless for two reasons. First, the Hamas members in Gaza will never allow the PA to conduct political activities there, as there is still significant bad blood from the 2005 elections that led to Hamas' bloody takeover of Gaza. Second, Israel will not allow Hamas to establish a significant political or military presence in the West Bank, which would pose a far more grave strategic problem than Hamas' presence in Gaza. If nothing else, Mashaal needs some way to remain relevant and he gets pushed further and further from Israel. Indeed, the unity deal largely harkens back to Yasser Arafat's successful maneuver to become relevant after its 1982 expulsion to Tunis by piggybacking on the First Intifada and become the center of attention at the Oslo Accords. For Mashaal, the unity deal with Abbas, from a pragmatic standpoint, presents his last best hope to remain relevant in the Palestinian political scene while potentially outflanking Haniyeh by riding Abbas' coattails in the international arena, where the PA has a substantial advantage over Hamas.
Even in the Mashaal-Abbas unity group, there is still significant discord. The PA's proposed prime minister, Salaam Fayyad, is almost universally disliked because of his perceived moderate politics. But, he remains popular with many international organizations because of his historically moderate rhetoric and long history of government service. However, it is unlikely that the far more militant Hamas will accept Fayyad. The unity government faces the significant problem that the most internally popular candidates (more radical Hamas members) are the least likely to garner Western support. Moreover, Mahmoud Abbas himself, who has engendered many enemies despite his relative political weakness, consistently threatens to resign and is himself an old man. More interestingly, the bulk of the PA's leadership is still divided between old Arafat followers and persons who could be best described as secular nationalists who subscribe more closely to Fatah's nationalist ideology (modeled off Nasserism). Whenever Abbas leaves the scene, there will be an open question of whether the PA will even be able to put forth a leader who can stem the Hamas tide or if Fatah will be swallowed up wholesale.
While it is very easy to blame Israel for the failure of the peace process, an analysis of the Palestinian political scene makes it abundantly clear that no Palestinian politician or faction can even make peace on behalf of the vast majority of Palestinians or even Palestinian leadership. Hamas, the stronger political force, is extremely fragmented, while the Palestinian Authority, the West's peaceful darling, becomes less and less politically relevant and more politically desperate (willing to partner with Hamas, which massacred Fatah members in Gaza a short seven years ago) by the day. All of this, coupled with the fact that any of these factions or politicians would be significantly weakened and made extremely unpopular for making significant concessions or agreements with Israel, it is very difficult to imagine why any would take significant steps to seek peace instead of first consolidating power, however long that will take.