I'm actually more concerned about us requiring EU's to have full 10-yr passports to visit here; where currently they only need ID cards to travel round the majority of Europe. So to come here and give us their tourist cent, they will have to find £70-odd for a passport (+ application + waiting time) and I bet the majority say "no, thanks" and spend elsewhere.
Why we can't continue to accept ID cards is beyond me, and in any case it's hardly for security when those with ID cards can get into Ireland and cross over into the UK without passport in future. It's just illogical, but when has Brexit been anything but illogical?
it's not a big deal at all.
when buying a ticket currently, all people need to carry "official photographic ID".
in the overwhelming majority of cases this is a passport or national ID card.The machine readable and biometric passports also work for japan,australia/NZ,Canada,USA and a few more, and is reciprocal.
it is theoretically possible to travel using a driving licence but not that many people have done it.
the only thing that changes is the requirement for 6 month validity remaining on the document, which is par for the course in almost every other country you travel to, and even this can be waived in extenuating circumstances(ie 3 months left and on short notice call out etc)
As for border checks, all electronic barriers will carry on as they are.
no reason to be worried about passport waiting times, if you really really need it and are prepared to pay, you can get a passport in 24 hours.