A recent interesting example for me was at our national seminar where the application of happo waza (8 directions) was explored with multiple uke, it saw relatively experienced aikidoka tripping over their feet and not knowing which way to turn, this despite doing the happo waza 4 times a class, 2 times a week 50 weeks of the year, it was an interesting example of the traps of blocked learning.
I would see waza as a1st approximation of aiki, paired practice as examples of aiki that might allow one to discover aiki in time - get the odd glimpse.
This is quite common and one of my major gripes. For example teach/learn the 20 jo suburi (Saito method). Then string the suburi together into the 31 or 13 kata and folks fall apart - work 'ti they get it. Then 13 or 31 paired practice - fall apart again - 'til the rework and learn it anew. Same for the kumijo. Now drop them into a more or less free style interaction and they fall apart again.
Even folks that are really good at awase or ki no nagare forms of the 13, 31 or kumijo when placed in an unstructured freestyle arena don't comport so well. What are we learning in such a format - patterns of movement but not how to move. Very frustrating.
Kind of the crux of the waza vs aiki thingy.