I think the "stand and fight to the bitter end" mindset is pretty endemic of D&D and the vast majority of d20 games, particularly those where magical (or a reasonable facsimile of) healing exists or characters have "buckets of hit points" (D&D 4e primarily but Saga Edition as well, though the later made up for it with weapons that had a much higher default damage value than D&D). D20 Modern and Babylon 5 were among the few d20-based games where getting into a shootout and not seeking cover tended to lead to dead PCs.
From the three sessions that I've played so far, the only character to really stand out in the open for the most part was my Force-Sensitive Smuggler/Scoundrel, mostly as I had the Ongoing Effect for sense, so I could make whoever was shooting at me have a much harder time of hitting me, and that was only for the first combat against a bunch of mooks. The second serious combat was against a bunch of Tusken Raiders, and the two shooters they had were taken out before they could even act with the rest simply not able to reach us to engage in melee, turning the fight into a turkey shoot for the PCs and with the last two surviving Tuskens bailing the scene before the blood-crazed Trandoshan Marauder could carve them up with his vibro-knife.
In the second session, when faced with a bunch of stormtroopers, everyone but the Trando sought out some kind of cover, and even then my character was the only one to escape that fight unscathed (being able to inflict a challenge die and a setback die helps a lot in that regard). The Trando however was built with an abnormally high Soak Value (a 7 if I remember right), so he could afford to stay out in the open, but even still he wound up taking a few solid hits, quickly seeking out cover and needing a stimpack after the fight, though anyone else would have been KO'd if suffering the same number of hits.
For the one-shot I ran this past weekend, one player (whose played almost nothing but d20 games) got a very rude surprise when his Wookiee got dropped in the second combat encounter, and he played much smarter in the remaining fights, making use of cover and any setback dice that could be inflicted on the bad guys to get close enough to engage the enemy with his vibro-ax. The players that had played other systems, such as D6 Star Wars, Deadlands Classic, and Savage Worlds, had no problem with playing it smart and making use of cover to protect their tender hides.