Date: 201601
Local time of day: 0601-1200
Location: DEN.Airport, CO
Flight conditions: VMC
Aircraft: A319
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Descent
Airspace: Class A ZDV
ATC / advisory: Center ZDV
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Workload; Situational Awareness
Second reporter function: First Officer; Pilot Flying
Anomaly: ATC Issue All Types; Deviation - Altitude Overshoot; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: Procedure; Human Factors
Primary problem: Ambiguous

Narrative: Aircraft was descending to FL300 approximately 30 miles from JAGGR intersection. ATC issued a four part clearance; 'descend via the JAGGR 3 arrival; except maintain 290 knots until DANDD; then resume published speeds; Denver Altimeter --.--'. First Officer (FO) as the pilot flying began adjusting the FMC to adjust the speeds; while I set the bottom altitude 11;000.  Apparently; the FMA was ALT* versus ALT when this happened; as the airplane continued descending very slowly to 29;600.  The FO immediately caught the error (JAGGR is at or above FL300) and I requested and received a clearance direct CLPTN voiding the next two altitude restrictions.  I take complete responsibility for the mistake in handling 4 issues instead of verifying the aircraft was flying the correct altitude.I offer these observations on the current RNAV SID/STAR procedures:1) The RNAV procedures are in direct conflict with our 4 operating priorities.a) Not as safe; as we are spending copious amounts of time making sure of all the restrictions instead of flying the plane.b) Uncomfortable for our passengers; as we speed up and slow down to meet these tight restrictions.c) Not allowing us to be on time; as we fly these published speeds whether there are other planes in the vicinity or which direction we are landing.d) Inefficient; as we use power and speed brakes to meet restrictions that are simply too demanding.2) The RNAV procedures force considerable threats from a CRM/TEM perspective.a) Each fix with an altitude or speed restriction is a 'threat' to the crew.b) We combat the threat by preparing for it (verifying each restriction independently).c) Inevitably; we 'repair' some threats by changing descent modes; adding power; or using speed brakes to get back on the profile.d) Finally; occasionally we find ourselves heading toward a UAS; as this report points out.The Final points to consider in the danger of these procedures are the 'newer' clearances we are receiving. The 'Maintain' clearance.  As opposed to the old 'Climb and maintain' clearance; we are starting to hear 'Maintain' clearances; which are not inherently logical (how can I maintain an altitude I'm not yet at?)The 'Climb via the SID' clearance issued after departure; which may require us to go 'heads down' to search multiple pages of SID instructions; to find the top altitude hidden in small font somewhere on the chart. Perhaps each SID/STAR should display the Top/Bottom altitude on the top of the chart in BOLD numbers?The true solution may come from the past; where for example DEN had the 'profile descent'. This allowed for a crossing 35 miles out between 17;000 and 23;000 which allowed all aircraft types to comply with this one restriction; then descend to one altitude prior to arrival (safe; comfortable; on time; and efficient).  Also; PLEASE consider ATC clearances of 'climb via SID; top altitude XXXXX'; or 'Climb unrestricted and maintain XXXXX'.  Safety should not be a matter of semantics.


Second narrative: [Report narrative contained no additional information.]


Synopsis: A319 flight crew reported RNAV arrival procedures; using the JAGGR STAR at DEN as an example; are increasing workload and asserted they are 'not as safe' as previous descent procedures.