Building a probe involves tradeoffs. (And remember this probe was designed during the Reagan and Bush 1 Administrations, when you consider the technology, and built during the Bush 1 and Clinton Administrations.)
They don't have a rotating camera. It's fixed. The whole thing spun while descending so it could photograph all around it without the extra machinery of a rotating camera. Unfortunately that meant it could only take pics on direction while on the ground.
Huygens was tacked on to another probe, Cassini. Much of the weight for Huygens was the heat shield; they could only fit so much stuff on.
Of course, if money wasn't been flushed down the toilet on the International Space Station, etc. we probably could have a specific Titan Orbiter with radar surface mapping, a Titan Rover, etc. by now.
"movie' of the descent
http://www.esa.int/esaCP/SEM5YW71Y3E_index_1.html#subhead1
Seems like for the multibillions of dollars spent, they could have thrown in a stepper motor. All it had to do was spin around and take a photo every few degrees.