I generally cook for me and my family, and none of us mind the skin, though if i do peel them there is a bit of difference in the taste, maybe because of the quick boil they have before peeling, maybe because more of the inside is exposed to the sauteed vegetables (not so in the simple boiled sauce that is blended though). As for seeds, i notice that not all seeds are bitter, and some tomatoes have few seeds.
I also don't peel, besides for the added work, because inside the peel is some of the reddest and tastiest part of the tomato. I find myself wanting to scrape it off with a spoon, one by one (and no way i ever really should be taking that kind of time). It's not easy to get the very fine layer of peel without taking that outer part of the pulp that has reddened under the sun.
I do agree the peel detracts from the sauce, and makes the pieces of tomato stay separate instead of sort of coming apart so they mix well with the pasta. In a restaurant i would peel.
just to add a note that is a little but not too much off topic and has been said before, i know.
If you don't already, mix the pasta with the sauce thoroughly. It prevents the pasta from becoming gluey and stuck, and gets the flavor through it. Presenting it with the sauce poured in the center of the white pasta is in no way traditional but far more relevant, doesn't taste nearly as good. In fact, better yet, toss the pasta in the pot with the sauce and finish cooking the last minute in its sauce.