I say do it, as you can see in my pic my essence sits write by an MIM classic P that Ive owned since 06 and IMO is just as good as any Any AVRI that I've owned. (an AVRI 74 jazz is in the pic as well for that matter and I've owned several AVRI p basses). I have played that classic P for years and it will never go anywhere. Unless your incredibly bonded to the P. I say do the trade and pic up a classic P on the cheap later for your P bass fix.
my '06 MIM Classic 50s P (Honey Blonde) has been silly good as well...it always tempers my GAS for a 'better' P. The neck has been unbelievably stable despite it living with me back and forth from Canada to Korea and now in China - even taking the neck off for packing in checked bags only required reattaching, restringing and a tuning...great basses and I assume the current series are just as good - recently just missed out a great deal for a lacquer model...
Have ALWAYS wanted to even touch an Alembic! Congrats to the owners here.