you are not crazy! lol. based on what you already have, you clearly do have a hole in your collection, and a tote is a must-have for a busy mom like yourself.
i think the neverfull is great, and the mm is plenty big. i would not recommend the delightful (any size) as a "mom" bag because of its single strap. don't get me wrong, i love my delightful pm, but it's definitely more convenient to have double straps when you're out and about with the kids. if you need additional security for an open tote, you can always get a purse organizer.
for more security (i.e., zipper), it seems the totally is a popular choice. also, i just saw this pic of emily maynard (bachelorette) with her daughter carrying (what i am guessing) is a cabas of some sort? sorry, i am not very familiar with this bag, but it looks sleek, simple, and functional for those who may not like the outside pockets of the totally, but still want a zippered tote.