FWIW Liara also got a boobjob. I guess all these ladies had a little more developing to do over the years, lol.
That's more common than one might think in video game productions. A lot of artists start with a physical model (who they in some cases did not pay to use as a base) and then build their model/portrait on it. Remember the Neverwinter Nights scandal when several of their portraits were practically identical to some celebrity photos? One was virtually identical to an angelina jolie photo. Not surprised they just grabbed a royalty-free image for Tali, TBH.
Found the thread I remembered seeing it in, but unfortunately it looks like the image links are all dead. 9 years old :/
It's lazy and they did it to cut costs, it has nothing to do with art or how they thought she would look. Her hand for example is not even proportionate to what the Quarian's hands look like, it wasn't designed or thought out, it's a quick Photoshop edit to save money, the same kind of crap they did on Dragon Age 2.
Designing a character based on a real model is fine, I never complained when they modeled Miranda after the real actress, they put the work and effort into actually designing her in the game and making her a character, with Tali they found a photo online that they thought looked interesting, did a 30 minutes at best Photoshop edit on it (if it took them longer than 30 minutes then whomever does their graphics design needs to be fired), then said we're good to go. It's cheap and it's lazy, done to cut costs.