Having multi region accounts on a PS3 or PS4 is not a hassle, I have US, EU, HK and JP accounts, all of them has credits in the wallet, I also have at least one disc game from each region, several Gundam games from JP, Heavy Rain and GTA IV from EU ( R2 ), MGS 4, GT5, etc from US, BFBC2, Mass Effect Trilogy, Uncharted Series from HK/Asia. I always buy from whichever region is the cheapest at the time
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I'm currently have HK PS+, all contents from PS+ works on all other accounts, so unless Sony change their policies on PS4 content sharing, it will still be the same.
I find it to be odd, if PS4 only needs 1 PS+ account to enable all users to play online, but imposing limits on region of the said users, while DLC, digital download and disc games installed from different region/store will be accessible on all accounts regardless of region - hence region free games where you can play any region PS4 games on any PS4 - just like in PS3.
Online play access across all users on a single PS4 is separate from DLC region locking scheme IMO - as all region free games have DLC purchase locked to each region they are released on, but accessible to be played offline + online on all accounts in one console. I have BFBC 2 Ultimate Edition Asian region with free Battlefield 1943 bonus and all the map pack, I can play all of them on all accounts ( JP, US, EU ) including buying account region ( HK )
Maybe have a PSN HK for PS+ for online gaming and have a UK or whatever account for downloading stuff (You can still download content without PSN+)?
That's what I would do if I have PS4, HK PS+ for gaining access to online play and whatever bonuses from HK store are basically added value, and the rest JP, US, EU accounts for every disc games/ download / DLC - whichever the cheapest

I'm optimistic that other region accounts will be able to get online play, as I can use HK PS+ account to play other region games installed on the console anyway.
For example - US DriveClub with DLC bought from US store can still be played on HK account which have PS+, Sony won't lock out the content to single region account it was purchased - that would be dumb and very restrictive if they promote region free games as a selling point.