PADI OW is four water dives. To my knowledge has been so for decades, including the 4 years I assisted on those checkouts. Unless they've changed things, which I guess is possible.
Goes like this:
Dive 1-- some skills.
Dive 2-- some more skills
Dive 3-- some more skills, maybe a bit of swimming around.
Dive 4-- the "mini dive" where students plan and execute it all with a pro just trailing & keeping an eye on them (this came in about 2015).
Prior to "mini dive", dive 4 was to finish skills and then a "tour" for maybe 20 minutes (?).
So, I presume dives 1-3 have more skills than they used to because there are none on the "mini dive" (dive 4).
This is an approximation-- if I'm off a bit an active instructor/DM can correct me.
Either way, you're spending 2 days of 2 dives each doing skills instead of just diving around.
I believe you can do 3 dives in one day and one the next day, but that's splitting hairs.
ChuckP, Are you saying you do all the OW skills on dive one and 2-5 are just regular boat dives with no skills? Can't be, but that's how I read it.
I can see where if it's one on one it could be possible to do all the skills on dive 1.
I'm certainly no PADI Standards expert, but it sounds like doing all skills in one dive is not within them.