Was the introduction of the A320 flight control system controversial?
Summary

No. The aspects that are talked about now are not the ones talked about then.

My (hazy) recollection is of concerns that the A320 lacked a system of cables and pulleys of the sort used by the Wright brothers. Perhaps pilots of the time had more focused concerns but I don't recall them making the front pages of newspapers.

In the 1980s there was discussion of Airbus flight control systems but the discussion focused on factors that were not involved in the most notable A320 crashes in the late '80s and early 90's.

Several Airbus accidents seem to be at least partly the result of pilots lack of familiarity with sophisticated aircraft systems in general rather than with features that are not found in other aircraft. 

The Airbus control system

The main innovations by Airbus were the application to civil airliners of designs that had previously only been used on other types of aircraft.


Fly by wire. No mechanical cables, pulleys and associated friction.
Sidesticks. To provide clearer view of displays and greater pilot comfort.
Flight envelope protection. To prevent excessive inputs stalling or damaging the airframe.


Transfer of control

Airbus spent some time comparing and investigating support for transfer of control between pilots, including in emergency situations. They investigated pilot preferences for several approaches to this. They revisited this aspect over the years and it has become a point of focus since the AF447 report. However it doesn't seem to have been a particular point of controversy in 1987. Perhaps few people in the 1980s fully realized the extent to which pilots can operate independently and antagonistically in severe emergencies and the degree to which teamwork and communication disappears.




  There were multiple severe accidents briefly after the entry into service of the A320


You mean these:


26 June 1988, Air France 296. Pilots flew aircraft into trees during unrehearsed demonstration flight at unfamiliar aerodrome after mistaking trees for grass on approach.
14 February 1990 India Air 605. Idle/open descent mode engaged and pilots failed to act as aircraft descended into terrain near airport.
20 January 1992 Air Inter 148. Aircraft flown into terrain after autopilot incorrectly put into vertical speed mode and entered numbers appropriate for flight-angle mode. Air Inter had chosen not to equip aircraft with ground proximity warning system.


The total number of hull-loss accidents for the 320 doesn't seem high compared to other aircraft, but it's hard to compare the numbers if you don't take into account fleet size, cycles flown etc.




  the A320 seems to have a very aggressive manipulation of the aircraft controls 


I'm not sure what you mean by "aggressive manipulation" but that seems an extreme view. The Airbus systems are a progressive development of existing trends. The accidents were largely the result of pilots setting inappropriate modes in systems like the autopilot. The accidents apparently didn't arise because of, for example, the way the control sticks operate.




  Was there ever any questioning of the Airbus augmented control prior to the introduction to service?


By "augmented control" I guess you mean features like the flight envelope protection that prevents pilot inputs from overloading the airframe. That doesn't seem to have been controversial.

The only controversy was over two items that had been used in military aircraft but not in commercial passenger aircraft


fly by wire
sidesticks


These don't seem to have been a large factor in the specific accidents mentioned above.



Further reading:


Indian AIr 605 - A320 Special Final Conditions - FAA
Pilots in the loop?
Electrical Flight Controls
Fly by Wire
AF447