From the very beginning of my sauce research, I never wanted to add fresh herbs or spices, especially garlic and onion, for one major reason: flavor concentration. I am familiar with the taste of fresh garlic in all kinds of dishes, and I think it's suitable in many cases, superior in a few. The problem I see is in the constituents of the fresh seasonings that don't contribute to flavor, namely water. The way I look at an ingredient is basically like this: structure (e.g. cellulose, protein), inorganic nutrients (e.g. minerals, salts), sugars, essential molecules (e.g. alkaloids, aldehydes, esters, phenols), and water. Since the tomato comes with its own water, water from the herbs and spices just isn't necessary, and in my case where I'm trying to maintain a certain specific gravity (density) for my sauce and a little extra moisture is already in play from MAE, it's unwelcome. Unless you're making a paste out of the fresh garlic, some of it will be going to waste since the sauce will only leach from the surface of the garlic.
With that said, anybody who likes to use fresh garlic should try it. My reasons for not using it shouldn't prevent someone else from doing it. If you roast your garlic and crush it into a paste with a mortal and pestle, you will likely get a very good ingredient for a pizza sauce, and then there's no reason to microwave it. That's the only way I would be inclined to do it other than what I do now, but it's time prohibitive for me. I have also used Amore Italian Garlic Paste in my pasta sauces before, but that's because I also add olive oil to my pasta sauces. I don't add oil to my pizza sauce because water is a better solvent that oil when it comes the cold infusion of seasonings. When I make pasta sauce, I make it on the stove for immediate consumption. If I decide I want oil on my pizza, I add it to the dough just before applying the sauce.