The next gripe I have is that they don't seem to have consistent syntax. What do I mean? <lj-cut> vs. <lj user=""> for example. I think they should all start with <lj and then have a space and then the type of tag and data inside, etc. Then the syntax could work like <lj cut="text"> or they should all use <lj-command modifier="blah"> as the syntax. Mixing and matching is too inconsistent and confusing. (I think I'm leaning towards lj dash command space modifier equals syntax, on second thought...)
Also, being able to close the lj-cut tag would be nifty, so you could mask off selective parts of that entry...