My experience of the last 35 years (as an adult, active parishioner) is that the system in the GOAA has essentially reversed the manner in which priestly assignments occur. It probably was too lay oriented, with bishops, too frequently, ratifying arrangements. However, the current system in the GOAA, mostly, is not even in compliance with the hierarchally leaning Uniform Parish Regulations (UPR), wherein, the bishop is to "consult" with the Parish Council, in matters of priestly assignments. They have taken away the interviews, too. 26 years ago, my parish had conducted an interview process among 5 priests whom the bishop had authorized for interviews by our Parish Council. In addition, the priest would celebrate the Liturgy and give a sermon. The process was respectfully conducted; each priest was asked the same question, responses were recorded by a secretary. The bishop ratified the priest the Parish Council had asked to be assigned, who was not the bishop's first choice. The selected priest from that process remained in the parish for 26 years. Too often today, I see wrong matches being made, which cause problems in parishes that take a long time to over come; way too frequently. I am adamant that the bishop's proposed selection should be interviewed, respectfully.
In reply to the original post, transfers between jurisdictions, including the "on-loan" type, are routine. I'm not sure of the percentage, but I believe the GOAA's Metropolis of Denver is composed of a very substantial percentage of priests who have been canonically received from other "jurisdictions."
In my years of active parish service, I've witnessed the reversal from way too much lay influence in ecclesial affairs, to way too much unilateral episcopal control, and I believe this change has not served the church well; a moderate middle ground must be found.