The La-Li-Lu-Le-Lo
That's very good but it doesn't resolve this exact issue. The map should still reflect better that it's a shopping centre by showing the centre's exact bounds. A multipolygon with a 'relation' to each shop seems to be the ideal.

I appreciate it's a big piece of work and editing programs are ill-equipped to handle this, but leaving it open in case someone is prepared to take this up - personally I'm not confident I could do it without damaging the bespoke data we already have on the shops inside.