I was immensely inspired by Suz's pragmatic and objective shoe collection analyse.
As a fellow shoe fanatic I really needed to make a similar analyse, which would provide me with a clear vision of the status of my shoe collection and help identifying actions to be undertaken.
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Method

First of all, I filed all my shoes in four categories :
 - Classy and Fancy, for shoes I would wear for special occasions ;
 - Everyday Workwear, for shoes I would wear for a normal work day ;
 - Casual, for shoes I would wear during the weekends but would not be suitable for work ;
 - Utility and Gear, for outdoor shoes (incl. horse riding boots) and athletic trainers.
I excluded flip-flops, indoor slippers and gardening boots since I have just the ones I need.

Then I defined the following evaluation criteria, grouped in two categories corresponding to my main shoe concerns.
 - Wearability criteria :
  - Size
  - Heel height and stability
  - Comfort
  - Quality
  - Condition
  - Special requirements (ex. requires special socks or hosiery)
 - Consistency (with my lifestyle) criteria :
  - Number of wears (approximate)
  - Duplication
  - Style (relative to my style aspirations)
  - Weather resistance 

For each criteria, I defined a set of numeric values : 1 if perfect, 0 if just OK, and several negative values in cases of issues (down to -5). I won't detail the specific values in this post, but in case someone would be interested they can be read in photo #1.

I evaluated each pair of shoes I own in regard to those criteria.
The evaluation was subjective, as it took into account the conditions in which I intend to wear the shoes : for example, I would consider fancy pumps perfectly comfortable if they only allow me to walk around the house. However, I would expect much more from my tactical boots, which must be up to extreme situations (ex. acting as observer during a military exercise, dealing with a natural disaster, surviving a zombie outbreak).

I then added information about the seasons when each pair of shoes is suitable, gathered all the data in a spreadsheet, and inferred a few graphs and statistics.

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Results

 - I own a total of 47 pairs of shoes, actually less than I expected. Maybe I've been more rational with shoe shopping than I thought. Or maybe my perception of a sensible shoe collection is skewed.

 - 42% are for everyday workwear, which sounds sensible.

 - [ETA] 28% are for utility and gear, which, from a temporal point of view, is not really in line with my actual lifestyle. They cannot really be culled though, as those shoes are mostly highly specialised for different activities and I do need them all at least once in a year.

 - (ETA, thank you Sara L.!) I have as many fancy shoes as casual ones. This is not in line with my lifestyle at all, since I wear casual shoes much more often than fancy ones.

 - There are 7 pairs of shoes (15% of my collection!) that I've never worn and/or not consider safely wearable. Six of them have a much too high or much too instable heel and will be donated. The seventh is a pair of pumps that are slightly too wide, and will be altered to become wearable (by adding a strap).

 - There are 5 perfect pairs of shoes - i.e. shoes that had the higher possible score given my criteria. All of them added as Finds. All of them are from the Utility and Gear category : they are my Dubarry's tall country boots, Haix tactical boots, Meindl polyvalent hiking shoes, equestrian booties (I forgot the brand), and Salomon trail running shoes. The first three of them are also the most expensive shoes I ever bought. I added Finds for most of them - like a Hall of Fame for shoes!

- (ETA) 5 pairs could be improved by easy, minor alterations, such as adding adhesive no-pain pads or replacing the insole. I must do those alterations.

 - There are 3 nearly-perfect pairs of shoes - i.e. shoes that have only one minor flaw. Two of them are workwear workhorses (Geox black booties and Noyce blue camouflage sandals), one of them is a pair of high shaft hiking boots from Aigle (also blue camo!). Added as Finds as well.
  
 - Nearly half of my shoes collection (48%) is suitable for all four seasons in my climate. Good news. But I have significantly more summer-only shoes than winter-only ones, most of them dressy/fancy or workwear. This is not really in line with my lifestyle, since summer is not my dominant season. I need to prevent myself from buying more sandals (*sigh).

Thank you very much to the brave fabbers who read all of this! I hope it may be useful for someone.