Altough modern cockpit technology have increased the accuracy of flying, it has also increased the the workload in the cockpit
Not necessarily so, unless you let automation completely dominate the flight deck in the arrival phase. And many crews fall for that. If I recall Boeing recommend against heads down programming below 10,000 ft which is proof that heads down programming in busy areas can significantly increase pilot workload in the cockpit.
Intelligent use of basic navigation techniques including the RMI needles and a DME, become an essential cross check fall back in terminal areas. The Cali accident was avoidable if the crew had simply tuned the required navaids in front of them and simply pointed the aircraft in the right direction rather than go heads down pressing buttons to get Lnav track.
Like the Cali accident,the Thai International A310 crash at Kathmandu was directly due to poor airmanship (pilot error) where the captain and first officer basically had not the foggiest idea of the true position of their aircraft after circling aimlessly both pilots heads down in high country without cross-checking with basic navaids such as VOR and NDB and DME. The increased workload mentioned above is purely pilot induced and manufacturer's recommendations fatally ignored.