Since 2.3, an average sightseeing tour for me is only worth 1M, in places where it used to be 4-7M. And 1M exploration data seems a little high to me, too. I'm more seeing 2x1.2M an hour for average sightseeing tours now.
I dunno.
I got a 5c passenger cabin fitted into my AspS at Wrangell Dock, in Ross 584, last night and immediately picked up a ~500Ly passenger mission which paid Cr3.7m (without making any efforts to ally myself with factions there, although I've been around Sol for a while so I might have had some rep in the region).
Maybe it's the result of spending time exploring but I tend to scan every star I visit, as well as any stars/planets that are within range of the jump point.
At the end of the mission I flogged the data for Cr1.5m.
Took my Orca to the same place immediately afterwards (until that point I was using it to haul cargo), fitted cabins into it, took on 3 similar missions and earned a total of Cr10m from them.
It might be possible to earn more by doing high-value cargo runs in something like a Python but then you've got all the hassle of attracting pirates and bandits, which you don't seem to get with regular tourism runs.