I believe in using regulation hurdles and do it often. I think it’s the best speed work method for those that can handle it. I think at a certain level you learn the rhythm and technique better when using regulation vs. non regulation. I view the issue the opposite way, why do you feel ‘cheating’ the hurdles is better? I don’t believe that it really is any more stressful, especially when some cheating (like I did today in practice) is something like a 10-12 inch difference in distance. Also, some athletes aren’t ready to three step in a race and I feel ‘cheating’ the hurdles doesn’t change that.
Having said that, I use non regulation spacing and height every day to teach rhythm and prepare kids for the next level in the event. I also do speed work with non regulation. I will use it to build a quicker rhythm or sneak it in to build confidence. However, I NEVER use a full set of 10 hurdles. That might work for some coaches but when I have two oddly spaced meets in a week I’m not going to put anyone over a full set of hurdles, regardless of spacing and distance.