Thank you for giving us a detailed account of your trip as promised, OP.

Serious reply:

Firstly, you should probably obscure your booking reference in your first picture as all one needs to access a booking is your surname and booking reference to have access to everything such as your address, contact details etc.

Looking through your post, I can only find one serious error by EK, which is applying a change fee to a Flex Plus ticket. I looked through the fare conditions for KWI-KUL itineraries in Flex Plus fares and the only fees they apply are for no shows (20 KWD for change, 30 KWD for cancellation). It is up to you as to whether you want to chase EK for the 10 KWD (33 USD) if they have incorrectly charged you. You would have to do that through the website and it takes around 2-4 weeks for that to be processed.

EDIT: I see you changed your mind on the change after seeing 10 KWD on the screen. However if you called in, they would not have charged you for that.

The rest of your complaint is really based on the idea you seem to have in your mind of EK promising you something, whereas actually that is not the case. For instance, where there is married segment upgrade availability, that is what they are showing you at that very moment. Incidentally, this is when you should take it because you can always refund them at the airport (except in very rare occasions - although you do seem to end up experience rare situations during your travels quite often ).

To get this straight - you refused to upgrade when there was availability on both sectors together because you wanted rows 6 and 8. As you are a regular visitor to this forum, I think you should have known that as those are both bulkhead rows, they are only available to be assigned at check-in at the airport, not beforehand. If you weren't, we are here on the board a generally willing bunch to give advice

Unfortunately, when you went to the airport, onward availability ex-DXB for upgrades (D class) had gone. This happens - perhaps someone else took the seat connecting from elsewhere. It's irrelevant what the agent told you at DXB because they have no idea why those seats were empty - perhaps they were all sold for cash and then there were lots of no-shows. Perhaps Y was overbooked and they were in the process of op-upping some pax. Who knows. All you know is that revenue managers were unwilling to open it up for D class availability.

That leaves space-available upgrades. You had a chance to buy the upgrade for 6000 miles less previously. Now it's closer to the time. They want 15k miles instead of 9k. They promised you nothing (in fact they were willing to process the thing for you, but you yourself declined). This is the essence of airline pricing: supply and demand. Now it's closer to the time, they can charge more and it's take it or leave it. After all, had you taken a 9k upgrade but someone was willing to pay 15k, you would be annoyed if EK then asked you for an additional 6k miles, right?

So really, your own expectations (e.g. feeling that EK promised you something when they actually didn't, and then compounding your own error by refusing to take an upgrade when it was available) have really conspired to anger you, rather than I think any external party...

I'm not sure if changing airlines will do much to make you feel happier because that doesn't seem to be where the problem is...

Non-serious reply:

I think previous posters have put it more eloquently than me Did you check to see if lotion has returned to the J lavatories? I did spy a small tube of it on my last flight...