In answer to your question:
were aircrew ever consulted in the development of this system
Undoubtedly! The MOD(OR) desk of the day would have been primarily involved in writing the requirement and significant in the down-selection of the bids received and the subsequent contract award. You can be sure that the officer concerned was aircrew but probably, as it was not then in Service, not a Tornado operator. That stated, he would have been constrained by: the interferers; the budgeteers; the political jessies; and any other gnome who thought he knew better! Believe me, I have been that soldier but post-JP233 era!
JP233 was a bl**dy good weapon and, as has been stated previously, 'fit for purpose'. The SG357 submunitions did do what they were designed to do, but the design was against a WP runway with European sub-strata and construction - not the soft sandy wastes that tend to absorb shock better. The HB 876 submunitions were very, very clever with different delays and anti-tamper that would have penetrated a bulldozer blade and the engine block had a WP chap ventured to mechanically remove them. Thus, I for one wouldn't have wanted to be on the end of a hose (no matter its power) because you would have been very likely to got a vf quick jet of tungsten in the teeth as the HB couped towards you (that was its design) upon the pressure that the water would bring to bear. Of course, that might have not been a problem for a WP Base Commander, but for his troops.....! The HBs could cover a very sizeable acreage from a 2xJP233 delivery!
The real problem for us was that most WP airfields had an SA-3 site off the end of the runway. The best delivery was either across or along the runway and both were practised regularly in coordinated attacks when we operated with JP233 in Germany. The problem with JP233 was that you had to be S&L at 500 kts as you ran in towards the release point and remain so throughout the delivery, which took about 15 seconds IIRCC! Thus, you had to fly straight at the SA-3 without deviation and remain so after you had overflown it! Not the best idea and thank God, we never had to do it for real in 2 ATAF.
foldingwings