I was resistant to squaring up units (trimming) for many years, as it seemed like a waste of time. The unit you've shown was typical for me in my non-trimming days. I think it was making a quilt with Edyta Sitar one time, where she said (in answer to a comment about her quilts looking so good), that her secret was that she sewed a scant 1/4" and trimmed up every unit (and if you've seen her quilts, that's a lot of units!). So I tried decreasing my seam allowance by a smidge with the aim of ending up with a unit that is just slightly larger than it should be, and then trimming. Once I experienced the ease and satisfaction of sewing accurate units together, I was hooked.
I think as long as you end up with usable units (that is, units that are 1/8" or less off), don't worry about how they look before being sewn into the quilt.