It seems with the end of "Time of the Doctor" and also the recent new trailer that's been released, that we are in for a period of The Doctor not knowing who he is and perhaps having to "find" himself again.

The question that should be asked is: Is this a plot development you might enjoy and how long do you want it to continue for?
Short episode based amnesia or season long arc?

Personally, as much as I'm looking forward to 12 and think Capaldi is an amazing actor, I'm approaching a potential amnesia plot with a bit of a sense of dread.
As much as it can be handy for "new readers start here" re-establishing the series with a new lead for new viewers, a lot of my enjoyment from the show comes from the Doctor knowing who he is and from that the knowledge or confidence for exactly how to approach any given situation

So personally I'm hoping the memory loss lasts for a short period at the start of episode one, use it to re-establish some key tenants of the new series, then have it all flood back and we can get on with the story.

Thoughts?

It will last for the same amount of time it took for 11 to reach that hospital rooftop or 10 to wake up.

About 10 mins before the episode ends then

Memories define a person - they are the building blocks of a person - without his memories the doctor will not be the doctor - he may have certain ingrained values left even in amnesia, but as an amnesiac it quite simply is not the same character. However, as a plot point involving the doctor trying to find himself and build himself back up again it could potentially be intriguing. But if they were to go with it for more than a few episodes, it would, quite frankly, be damn foolish of them to do so. Introducing a new regeneration of the doctor without his memories is effectively introducing an entirely new/different character and it would be idiotic to run with that plot for more than the first 2 episodes.

...the second episode would be interesting with amnesia....

You obviously know the plotline for the second episode, then.

Im not convinced that it is complete amnesia, as opposed to just a bit of major brain confusion. Take the one scene we have. He starts flipping switches and pulling levers like he knows exactly where he is, but then because he is suffering confusion say's do you happen to know how to fly this thing?" because he find he can't figure out how, but seems to know that he should know how.

On that basis I could envision them doing a quantum leap type scenario for a few episodes, where he mostly remembers who he is, but his brain is 'swish cheesed' and he has blanks, but on the other hand, I could just as easily see it being the bog standard regeneration confusion wierdness that is sorted within the first episode when he adjusts to the new body fully.