I would verbalize "Selbstvergewisserung".

"This proposal presents an opportunity to ascertain and ensure the quality of courses of study."

You could also write: "This proposal presents an opportunity to assess and ensure the quality of courses of study."

There appears to be a certain amount of overlap in the concepts of "nachdenken" and "Selbstvergewisserung". The two ideas go hand in hand.

Within this context, "nachdenken" basically means "to assess" the quality of education in Europe. Another way of saying this would be "to ascertain" the quality of courses of study.

It doesn't make much sense to me to write "...to reflect on the quality..." That would be a fairly wishy-washy term for an academic/political text. But you have more context than we do.

By the same token, I would interpret "Selbstvergewisserung" as "to ascertain" (in the sense of "to check") AND "to ensure" (to control = "kontrollieren).

Here are some entries from Langenscheidt:

vergewissern: sich vergewissern über v refl = ascertain

Sich vergewissern = sich Gewissheit, Sicherheit verschaffen über, sich etwas sichern

vergewissern Verb/reflexiv: sich vergewissern = make sure (einer Sache of something); check (something)

DUDEN Synonyme: vergewissern: sich vergewissern = kontrollieren

BTW, depending on how you have been translating "Bildungsgänge," you might be able to replace this with a more general term like "higher education."