Question Regarding Quick Exploration for Retainers

[Kirika-]

Retainer's exp level is the determining factor on the "level" of the obtained items in a Quick Venture, as in up to the retainer's level basically.
The retainer's equipment level (iLvl) will effect a "bonus roll" that can increase the quantity and quality of items obtained, you will see a message "Your retainer's gear was sufficient to earn a greater reward" in the retainer's report, however it no longer effects the rarity of the items obtained.
So, while under ilvl'ing your retainers does save you in upfront gear costs, it does gimp you in the items obtained a bit.

These changes were made in patch 5.4, within the System section:
https://na.finalfantasyxiv.com/lodes...8c2f1094131070

The following additions and adjustments have been made to retainer ventures:

New retainer exploration venture levels have been added.

The following additions and adjustments have been made to quick exploration:

New items can be obtained by retainers that have reached maximum level.
Retainers equipped with more powerful gear will receive items in greater quantities, with a greater chance of obtaining high-quality items.
* Following this change, the chance to obtain rare items based on gear has been removed.
Certain items previously obtainable via retainer ventures have been removed.
The amount of experience gained via retainer ventures is fixed depending on the retainer's level.