Taurus demon is absolutely the intended path. You have to go very far out of your way to skip it, and there's no way someone would find that method accidentally. I can buy going through Havel's door and not realizing you could go up, maybe, but not the whole drake/darkroot method- any reasonable player would turn around after getting their ass handed to them by the Drakes and Ents and Forest Covenant, and don't even start on going to Blighttown first. The other routes, and the Master Key in general, is more for people who have already play the game once and want to skip the Burg, which is pretty much a training wheels level.
Just because it's not technically exploiting any glitches or stuff like that doesn't mean it's not obvious sequence breaking.
We'll have to agree to disagree on certain points, I believe I understand what the developers were thinking when they put the burg and Taurus where they did, I just don't agree with the terminology, "recommended", "intended path", etc. the same way you appear to......the game is way more fun based on what items you wish to carry around with you to boss fights...and what type of character you conjure up plays a roll in that, as does the covenant you wish to join......not which order you do boss fights in. If FROM had an intended route in mind, and they probably did, it was the route I posted, not the "obvious" one the wikis promote. How could I possibly have a novel experience if I went through the game in some linear fashion, got all the EQUIPMENT out of order for the character I rolled, plus missed the point of what equipment I got from what covenant, to be used on said boss or PVP hotspot? Anyone that goes through this game in the "intended order" is missing FROM's real intent, which was to provide a facade intended order in order to obfuscate the true order (which is based on getting the useful items for whatever character/covenant/boss fight someone wishes to do.)
As obvious to you that you think the burg was intended as a "training level" (which I agree with) this will not appeal to everyone, and I believe FROM knew this also. Far less people than you think, who are cult followers of this series, enjoy going through the most popular order based on geographical logic. A very large cult following of demon's/dark players, including myself, enjoy the "road less traveled" approach that these developers tend to espouse...they couldn't even tell the truth to the distributors about what they intended to do for Demon's, this is a rebellious crew, and this beyond all other intentions, was what they set for their faithful fans in Dark. This rebelliousness was congratulated by their fans, and the master key and londo ruins door was placed there just as intentionally as was the burg. Each to their own, but to say that my wish to experience different areas of the map differently than others, find special equipment and items like the moss in darkroot, in order to go to blighttown, which in turn gets the gold hemmed set, etc etc. is reserved for second run through is ridiculous....that's the whole fun of the first play-through of the game for me, and many others like oracrest, who did their first playthrough without spoilers...its the feeling of being alone in a dangerous and unforgiving place.....the "let's play things safe" easy route exists for the masses, and sells more copies to people not liking the punishment of death etc. but the burg being easy was not for the true appreciators of FROM's REAL intent. IN Dark it was MANDATORY for me to experience the wide open freedom given to us BEFORE following some suggested order that the people making wikis (poor ones early on) thought were best, based solely on geography, perceived difficulty and soul counts etc.. This series is ALL bout the equipment, and the spice in 3.1 being useful for 2.2 in demon's and vice versa the dragon sword in 2.2 is best acquired prior to 4.1 made a pretty obvious path form.....which was out of numerical order, but was difficult to stray from without bending logic, but Dark was designed to try to fix that. Dark was intended to be different that way, and it was...more like oblivion, there were problems with PVP as a result, but that was why there were problems...the true intent of the design of dark was PURPOSELY to set a up a way for adventurous types to be rewarded by being able to get cool equipment faster than the "safe mode" people doing the easy areas first. So much so that it wrecked PVP a bit.
So although I agree the burg was intended to be an easy training level, it was intended to be that way necessarily to serve the purpose of gratifying the adventurer that prefers to have the freedom to explore as many areas as possible before going through the first boss door stumbled upon.
This is why I took the time to share the path at all, because I know there are lots of similar minded people that would like to do FROM's REAL intended route FIRST before they know where everything is. This route is FROM's recommended route, not just my own, and that is why I took the time to post it.