Wow, my impression of Moria on legendary has been (and still is) very positive. I just hit 54, basically just questing and deeding, and having fun revisiting it all. I have noticed small differences, mostly adding convenience in travelling between points.
Also, my personal light certainly keeps me from falling down a crevice.

Today I did the tankard quest where you drink to the fallen dwarf in various Moria locations - I remember travelling to each point on my own originally (and I don't recall if the locations were even mentioned in the quest dialogue) -
today I just got really drunk, to the point of passing out, then kaplooey!! I woke up in another zone near a new tankard.

I am surrounded by people all of the time in Moria, so it's not dead by my reckoning. Shoot, there are lots of people in all of the zones still - and I will be leveling one or two alts as I imagine others will be doing as well.
In Moria I plan to complete all of the questlines and finish all (or most) of the deeds - I try to play daily, so unless RL hits me hard I should be good.

To the OP's request, I am good either way. If I haven't finished all that I want to do in 4 months, I will just continue my quests/deeds and then move on to the next zone. I wouldn't be averse to 6 months for Moria/Loth either.
I am assuming they will adhere to their original plans, but it's all assumption until/unless they announce something different.

I am on Anor and I love the community there and am still having a blast playing. It has breathed new life into my LotRO experience.