The corner lot is 70 x 120, definitely big enough for a nice little infill building, maybe 5 or 6-storeys. I didn't mean to imply that it is undevelopable, rather, that it will require an unusual building with setback issues out of scale with the neighbouring towers.
The existing zoning is quite odd. It allows a 1.5 FSR outright, up to 4.0 FSR if you consolidate the entire block. The Vancouver House site had the same zoning but the site was rezoned and so the block consolidation wasn't required.
I have no knowledge of the owner's plans for the site, but it's safe to bet that they won't be retrofitting the dilapidated service station for a restaurant.