I was definitely going to visit Sweden this Summer to do the Narvik sleeper, but that's now a maybe as a result of my experience.
I was already in two minds about entering Schengen at Sweden, but the further reports in this thread have put me off completely. I still wish to travel to Sweden but I will now do so by going via a more relaxed Schengen country such as Switzerland.
Well The Europeans don't seem bothered about that ?
In the busiest Schengen airports a high proportion of travellers will be EU/EEA citizens eligible to use e-gates, and excluding British citizens has a minor if negligible effect. (I believe some airports in Spain and Portugal allow British citizens expedited entry because Brits are a large proportion of entrants.) But they already seem to employ sufficient staff.
Whereas if UK airports limited e-gate use to British and Irish citizens only, the e-gates would probably have no queue while the manual queues (at peak times at busy airports) might be so long that people would not be able to disembark planes from lack of space in the terminal. I almost experienced this 2 weeks ago at Heathrow. To ameliorate this, the UK would need to employ a lot more UKBF officers thus incurring more costs for taxpayers and/or increasing the passenger service charges levied by airports.
I do think that British and Irish citizens should have a separate manual queue in UK airports - last year at Heathrow I got stuck behind two sets of EU travellers who got extensively quizzed by UKBF about their travel plans (like the Swedish experiences reported above), but since there was only one officer processing this queue I had to wait for them to be done.