"Item quality is checked in the following order:
Using the above example, when your roll ‘misses’ a higher-level item quality, the item generator proceeds to the next lowest item quality in the chain (in this case, checking to see if you got a 6-affix rare, then checking for a 5-affix rare, and so on). Your magic find bonus applies to each roll. If the same monster has a 10% chance to drop a 5-affix rare item and you have 50% magic find, you now have a 15% chance to get a 5-affix rare item."
I thought it only affected whether a white item would be a blue, a blue item a rare, a rare item a legendary.
So, not only does it affect that (because I usually see 2-3+ rares with 300%+ MF with 5 NV) but it also affects the potential number of affixes a rare has?
If true, should unidentified items have the number of affixes displayed (mainly for buying/trading unidentified items)? The main reason is because that means there are potentially better unid rares with higher MF than with lower MF (more affixes).
(Besides that, seems unid selling/buying has slowed down since that topic that analyzed it was posted and being able to sell unid with 5 affixes [if shown] would possibly boost unid trading again.)
(Also, please "like" this post so we may get a higher chance of getting a response from a community representative.)
Edit 2 - It seems a bit unfair that MF hugely affects affix rates (if they do, they should be shown on the item even unid - to make it fair for unid buyers).
That's why 6 prop crafting plans are more expensive than 4 or 5 prop crafting plans - because generally more affixes = better items most of the time (which is worth more).
For example - Sure you can get an item with +75 AR, +9% crit, + 50% crit damage... but you could get an item that has +75AR, +9% crit, +50% crit damage, +9% attack speed, +200 DEX, and +200 VIT instead (which would be worth 10x more than the former).
With the way things are set up, it seems too required to either MF swap or use MF in general.