All these conservations are very enlightening, although I dont believe most have addressed my initial question. Should OW courses be allowed to be taught in 2 days?
I suspect most posters understood the question, and declined to answer it directly (I didn't initially comment for the same reason - I didn't want to say 'Yes' or 'No'.) But, since you asked again, my answer to your specific question as worded is 'Yes'. The caveat is, 'Certification should be granted only if performance standards are met.' That statement should technically be unnecessary, by the way.
I don't think PADI necessarily tried to dodge your question, either, rather the response focused on the real issue - meeting the stipulated performance requirements, rather than relying on some arbitrary time frame. This is the classic Structure - Process - Outcome discussion. What has been done by PADI (and probably other agencies) is a shifting of the emphasis from the Structure of training, or the Process of training, to the desired Outcome of training - can the student diver perform the skills that are required. The electronic pages of SB are filled with discussion / debate on whether performance requirements are adequate, whether standards are insufficient, etc. I don't see any useful purpose in opening that can of worms here. Most of us have our opinions and probably aren't going to change them, anyway. Personally, I see standards as minimums that must be met, not maximums that limit what I teach. Standards should be minimums, that are broadly applicable. Otherwise, we might require (as an absurd example) that drysuit use be taught as part of OW because drysuits are different from wetsuits, and a diver could potentially die because of runaway inflation leading to an uncontrolled ascent. I don't think 'raising' that standard would seem reasonable to those who teach year-round in 80+ degree water. For those instructors on SB who have successfully provided OW instruction and certification to some young(er), physically fit, intellectually agile, well-prepared OW students, in only two (long) days, changing a standard to a minimum of 3 calendar days (or more, pick a number) might also seem absurd.
As several posters have said, though,
you have to decide for yourself whether you are comfortable with the structure and process of training as conducted by the shop with which you are affiliated. If you aren't (which would appear to be the case, based on your first post) then you should either share that concern with the shop in an effort to change practice, or decline to participate in the training, or offer private instruction yourself, in a structure that you feel comfortable with. Yes, it would be nice for PADI to do it for you - for PADI to change the minimum from two days (which is really driven by the OW dives, not the academics or CW training) to something longer. But, you ultimately have to decide what is best for you. Personally, although my answer, above, was 'Yes', I would not be comfortable with a 2-day group OW course. But, that is me. We teach group OW classes in our shop over 6 calendar days (and charge $375), and I find even that time frame to be a stretch for some students. (We potentially compete with a shop that offers a 3-day class, and charges $259, and have elected to accept the fact that some students will go that route.) The emphasis in virtually every field of endeavor is 'Better, faster, cheaper', and the 'better' part often seems to be interpreted as, 'not conspicuously worse than'.
I can fully understand your expressed concern about the potential for accidents, even deaths, associated with inadequate training. If you are uncomfortable with 2-day classes because of that concern, you shouldn't participate. I think Andy said it very well, 'Unless fatality rates spike, there's just no business argument against shorter, cheaper courses.' And, I really doubt that spike will happen. In fact, OW training appears to have become progressively shorter over the years, and accident rates appear to be stable, or even declining, rather than increasing, not withstanding the anecdotal reports that fill the Accidents and Incidents forum.
Ultimately, if you are uncomfortable with the outcome of training being provided by your shop, not just the structure and process, you also have the option to change agencies. Move to one that mandates a longer minimum time frame for the OW class. Having said that, I am not aware of the (minimum) time limits of agencies beyond PADI, and am curious if NAUI, NASE, SEI, SSI, SDI, etc., have minimums, and what they might be.