Whilst I understand that this is in general a good thing as it will help logging in and server stability (I think?).
There are a couple of things that need looking at by ZOS before this is implemented.
Firstly, guild GMs.
If a GM of a guild has been away for the period that constitutes as inactive what will happen with the guild?
Will it be automatically disbanded or will it cause glitches within the guild framework?
I think that an officer from the guild should be auto promoted to stop any issues from occuring.
Next, is housing.
Most guilds are using someones primary house as a guild house; full of crafting stations etc.
If this person hasn't logged on for the specified period the guild will lose its house.
Unless using somebodies house could class them as active or each guild GM could message ZOS somehow and classify which persons house is the guild house and get that account locked so as not to be deactivated.
Guild housing could put a stop to this but seeming as it doesn't exist yet
Live a little love a lot send all your gold to this Imperials pot.