Have any other Palestinian leaders voiced criticism of Hamas?
PFLP
Lots of "Palestinian leaders" voiced criticism of Hamas, Israel targets these organizations with priority to bolster the presence of Hamas: a militancy unlikely to receive international solidarity.
Rabah Muhanna a senior official in the Popular Front to Liberate Palestine (PFLP) strongly criticized Hamas on Saturday over the way it rules the Gaza Strip since mid June 2007. In a statement to the press, Muhanna accused Hamas of failing to achieve the political partnership with other political factions, and taking exclusive procession of the Strip aiming at imposing its Islamic ideology on the coastal region. - IEMC,
And,
PFLP official Rabah Muhanna was one of many faction leaders who also called upon Hamas to sever relations with the Muslim Brotherhood. Palestine Chronicle
And to the extent that there is an unvoiced criticism,
"We have tried, so let them now try [...] it is their turn." - George Habash
My interpretation is that the PFLP had largely fallen apart, though they still exist and have a functioning militia. And the new form of resistance was both different and not something that would garner support from the PFLP.
Fatah (PLO)
On the other side, lots of the Palestinian elected leaders have expressed disagreement with Hamas. These organizations are largely rejected by Palestinians because though advocating for peaceful reform and discouraging militancy, they've largely gained nothing and only given concessions. Their presence as a functioning government is more of a PR stunt by Israel itself. For example, the PLO cut off funding for the PFLP, and was likely party to or responsible for the assassination of a PFLP member in the Palestinian embassy in Bulgaria.
- Arafat had the leader of Hamas placed under house arrest, and other senior officials arrested. source.
- "Nobody will dodge [Hamas's] responsibility. ... We didn’t want or need this war. What was the point? Did Hamas imagine that it could win?" - Mahmoud Habbash
- Hamas's policies and actions "do not represent the Palestinian people" - Mahmoud Abbas