On the topic of L5R 5th edition, I just wanted to echo Kimi's comments that it would probably be worth revisiting the game now that it is out. I'm just finishing up a review of the beginner game box set and really like the new rules and how the final implementation of the strife mechanic works etc (though unfortunately, I wouldn't recommend buying the beginners game due to too many small issues). It is very different from 4th edition though so I do think it is one where some good cheat sheets/player mats would be a huge boon.
As for lethality - I'm going to code something up to stress test it vs 4th edition but my current impressions are that yes, it is slightly less lethal but not excessively so*. A typical starting character has 8 endurance (HP) while a katana does a base of 4 damage plus any bonus successes from the to hit roll. So without any mitigation, two hits will guarantee that you incapacitate a character and it is possible to do so in a single hit. The big difference is armour, which only soaks damage in this edition and does not change the to hit TN (which is a fixed difficulty of 2). Ashigaru armour soaks 3 points of damage, so does make a big difference in most situations.
A question I've got for @Tappy - how has the game changed in terms of lethality from 1st through to 4th? I only came in at 4th and while it is definitely more lethal than D&D I didn't observe the number of one strike kills that I'd expected given how often people mention it as a selling point.
*based on the beginners game rules, things in the core book may be different.
The second thing is one for @Stork regards Fate based games - Do you think your issues with aspects is anything to do with character familiarity? I have had essentially the same problem with D&D and a whole host of other systems where I'm taken out of the moment by trying to work out how to best apply my feats/spells/abilities. Generally, I find that this is most noticeable early on while I'm still getting a feel for the character and how they work. After a few sessions, I'm more comfortable with the flow and I wonder if you would be similar with a longer campaign using Fate.