Hey Bakbik! This category exists already -- check out the All Worlds, 100% runs!
There is a category which is "all worlds any%" and also a category which is " all worlds 100%". There you have to finish all worlds, get all the crowns, all the skins. The only thing which is not included is "all achievements". There are only 5 runs and all of them have lots of deaths, so running with less than 5 deaths is pretty hard and barely any people will submit any run.
The only thing the new category would add to the current All Worlds - 100% run is death count, and since deaths add time to runs anyway, I don't see the point in adding a new category for that.
Bakbik, I definitely encourage you to do a run of All Worlds - 100%! Check out the current rules listed there, too :D
Yeah, the only change would be the need to do time trials for every world (that costs time, doesn't add difficulty), that have to be beaten in less than 5 deaths each. All Levels, Crowns and Skins are already done in AW 100% (Like Oxknifer said). But deathless(ish, up to 5...) is hard with crowns, especially Winda/Zipsa, which would make less people submit and you could lose 5 mins just by dying once too often in right left ("kinda" bad) (also said by Bigunit). The plays would stay the same, but some people might choose to use easier strats to avoid dying, which'd make the run less interesting. Add the longer menu times because of 4 time trials on that, and you have a worse AW 100%.
