As much as some people are going to come out with the usual "this is an MMO so no soloing" arguments something along these lines really needs to be considered for content that it no longer relevant. Due to level sync there is no way to out level or out gear content to the point that you could solo it. This mean a full group will be required for content that most people won't be interested in any more. A soloing option for getting players through content like that would be most welcome in my opinion.
With regards to coil though I'm not sure... Making those fights soloable with AI party members would be a LOT of work as they would have to completely redesign the encounters. There would also be the issue of the AI being stupid (come on we all know it won't actually be very intelligent). Finding a balance with regards to the time investment needed to implement this may be difficult.
