I know we have a general FEH channel topic but it seems like 75% of the population missed the second half of this particular announcement and instantly closed the video to type up angry replies on the internet.
Lets clear this up shall we: based on what was said in the video, the Book 1 5*s are only removed from summoning circles with new heroes. If the banner does not have new heroes or new seasonal units, you can get Book 1 5*s even if they aren't the focus like you can on any summoning
Oh yeah, you are right. I did the math, and it is slightly easier to get green and colorless Focus units (assuming the Focus has one Focus unit of each color), but it is balanced out by it getting slightly harder to get red and blue Focus units. You are less likely to be pity broken by red and colorless units compared to before, but you are also more likely to be pity broken by blue and green units.
FOCUS Pre Update
Focus
3%
Non-Focus