Hamas discovered the downside of pretending to be civilians in their war with Israel. If it makes it hard for the IDF to figure out who's who, it makes it easier for Hamas 'fighters' to run away.
From news article:
Another change is training and discipline of their fighters. Although Hamas has nearly 10,000 armed men on the payroll, most of them are poorly trained. Last time around, the Hamas fighters were eventually ordered to get out of their security forces uniforms and fight in civilian clothes. This was done a few days after the Israelis entered the Gaza Strip, and Hamas realized that its fighters were no match for the Israeli troops. It was believed that having these men fight in civilian clothes would reduce Hamas casualties. If it did, it was not by much. But seeing all those Hamas security officials ditch their uniforms made Hamas look cowardly, and weak. Hamas had already lost the support of most Gazans by allowing the rocket attacks on Israel to continue through late 2008.
So, next time around, Hamas security forces are being trained to fight, and stay in uniform. The new infantry tactics depend on avoiding getting into battles with the Israelis. Instead, sniping and hit-and-run tactics will be used. All this is a long shot, since the Israelis have been very quick to adapt their tactics to whatever Hamas comes up with. But Iranian and Hezbollah advisors insist the new methods will work. This is largely based on the relative success of Hezbollah in their 2006 battle with the Israelis. Hezbollah actually lost that fight, being driven out of southern Lebanon by the Israelis. But Hezbollah declared it a victory, and that counts for a lot in Arab countries.