I play almost exclusively open play. The only time I switch to Solo is at busy outposts, and it's less about avoiding other players, and more about saving time. (Not much fun to be had hitting Request Docking for ten minutes). I'm looking forward to the option to group with friends in open play, as I really enjoy the dynamic that open play offers.
I was thinking about the PvE groups though; whilst they are, in effect, a good idea, one potential scenario that could arise is that Open Play becomes known as the 'combat' mode, and alienates most other types of play out. Traders and miners will stay in Group play (because PvE is what they want), leaving only mercs and pirates fighting it out in Open Play. Whilst it does split up the playerbase well in terms of what they're looking for in the game, it doesn't leave any middle ground to which Open Play currently has.
With this point above, I really hope that Wings, and the ability to group and work together, tempts traders back into the open game. If you're transporting millions, and you have a friend or two protecting you, there's still an element of risk but it creates far more interesting scenarios than simply being interdicted by a player Pirate who's only goal is to blow you out of the sky. Inversely, pirates who operate together will have to share the rewards actually lose out working together, so the balance may change.
My final point is regarding fines; they're not much of a deterrent. I hide in Anarchy systems, building up my funds for a better ship, and attack in Federation space. My ultimate goal is to take those prizes and merc for the Empire, so those fines will never be paid. It does add a dynamic that I have a harder time in Fed space, but that's part of the character I've created. Worst case scenario, I can just save up the insurance, and go out in a blaze of glory against a bounty hunter (thus giving another player some fun, and a ton of money, in return) and respawn clean.