The hour before servers went down, I was randomly soloing coblyns in Nanawa Mines for about 145-170 SP each. When I logged back in after the maintenance was done, I killed a few to see how well the auto-attack worked, and at R24 I was getting 125-130 each, so IMO the SP reduction is not that much.
Also, to give you an idea of how solo friendly it is, I was 1000 SP away from Rank 25 after returning to Ul'dah. After doing the first Immortal Flames quests (quests give SP now), I dinged 25. As of this morning all I've done on LNC was turn in some more quests in the city and I'm already 6k in to R25--that's without using my lance at all lol.
As for groups, I've seen tons of people partying together at the camps and a lot of people forming up groups outside the R25 and R45 dungeons. There are people shouting for parties beyond grass raptor camps, so I'd say people are starting to party, but it's only been a day since the patch was released, so we'll see how that goes. I think soloing and partying both benefited from this patch in small ways.