"I am wondering if this would create problems and/or look like it was a screwup"

Both.

BAD idea.

There are plenty of square sinks out there. Plenty. No need to re-invent the wheel.

Not sure which Blanco Silgranite II Performa sink you are looking but in my opinion the curve really is minimal. Most people won't even notice the slight curve across the front and back. I have the Performa Medium 1 3/4. It is under-mounted and the countertop is flush with the sides of the sink. Here is a close up of it.
{{!gwi}}

The Blanco Precise looks like it is a straight edged rectangle. You might want to look at that on instead.

I have barely started my kitchen reno (waiting for some estimates) but I'm in love with this exact sink. I want to have a double sink, with the flexibility to wash larger items and this one fits the bill.

I hope you were able to figure out your sink dilemma!