Its strange because it worked for me the two times i played it without me trying to position the remorhaz in a specific place...

and as to the dimension door I dont think its chess unless you use it to bypass areas you were not meant to... using it to get to Hjollder on Burial Isle IS a cheese therefore, but its not cheese to use it to get amulet or in other fights to get your mage away when he gets swarmed by mellee..

Using it to get to Hjollder on Burial Isle IS a cheese.

I still don't think it is cheese because you are still forced to go underground after. There is no avoiding it, and I think it is better to do it with the door because if not you will likely find the ------- before Hjollder even gives you the quest.