The first point is that iphoto is behaving badly (IMHO) creating another event of the same name but with a date qualifier so it makes sense for ME to merge them. If you want iphoto to control your life events as it chooses then ignore the method.
iPhoto creates a new Event for each import. You perhaps might like to investigate the other options for organising in iPhoto. Events are organisation for those who can't really be bothered. They are automatic - based entirely on Date and Time the camera records the photos as taken.
If you're going to use iPhoto - and you shouldn't, really - then you should investigate the other more powerful options it presents: Albums, Smart Albums keywording and so on.
Second point is that my serious edits would be done in RAW and resultant jpgs can be imported after editing. Again this allows me to keep my separate RAW 'negative' files separately. The 'Edit in external editor' option is very slow and has hung my mac several times with the wheel of death.
iPhoto preserves the Original file untouched in every operation. You can always revert to the original file.
Final point is, as you will see from many previous posts, when these databases screw up their index they tend to trash your photos.
Well, if you actually read the posts and not the alarming titles you'll see that no, when the database goes west they don't trash your Photos. The catalogue is damaged but the files are perfectly fine. You do realise they are just stored in folders in the Finder, right?
Plus, like any data on any computer, the simple and surefire protection against this is an up-to-date back up. Your actual photos are at much greater risk from a HD failure than an iPhoto database one.
Yes of course editing any jpeg will lose some metadata every time it is saved. It's a flaw in the jpeg compression The 'current version' held in iphoto has already lost its metadata (it is saved as a jpg in iphoto library) and exporting it does not make it any worse. Also if exported with a suffix a,b,c all versions are available in the mac fielsystem. Exif data is preserved.
No, when editing a Jpeg no metadata is lost. Data will be due to the compressions system, but no, exporting as current does not preserve all the Exif metadata.
iPhoto is about lossless editing of Photos.
I regularly sit down at Windows machines and I find then confusing and difficult to use. But I don't assume that the problem is with Windows. If I'm going to use this machine for a task then I need to learn how the designers intended that task to be accomplished. I invariably find that when I do, then their workflow makes a lot of sense. I don't assume that the designers are wrong. I assume that they are quite bright people. If the app suggested to me for a job doesn't suit, I go look for one that does the job that I want done.
You choose to work the way you want. You're a grown up. But your system is pointlessly complex, lossy and based on a misunderstanding of what iPhoto is, how it works and what it's for. If you took a few moments to explore the app you might find that it can actually do what you are trying to achieve and do it more easily than you're doing right now.
Regards
TD