I did an online class followed by one day of pool diving, and then I did two days of open water diving. I was under water in the pool for about an hour and 20 minutes, and then had four 25 minute open water dives
The only work took all of about 3-5 hours since I skimmed over much of the course and went right to the tests. The vast majority of the information is common sense coupled with knowing terminology. Some information, like the dive charts, and the hand signals required study, but all-in-all, it took very little time. Classwork is frustrating because you go at the speed of the slowest person. An online course is much more preferred.
You learn everything you need in the pool anyway. There is not a single thing I did in my open water certification that I hadn't already done numerous times in the pool. Between the pool and open water dives, I must have filled my mask up with water 10+ times. Probably 15.
Learning how to equalize, hovering, and just generally being comfortable breathing underwater is all I learned, and really all I needed to learn (beyond the hand signals, depth gauge, familiarity withe BCD/regulator). The subsequent open water dives are just to get you more comfortable doing what you already did in the pool.
It took me 3 days in the water (one day in the pool; two in the open water), I would have been comfortable doing it in two days.
I would imagine the schedule is one day in the pool, and then the open water dives are just two longer dives where you don't go down very far in order keep your pressure group low.
I don't think it's a big deal.