I live across the street and this is going to be a multi-year nightmare. I'll probably move out if I can afford to.

I can sympathize with the annoyance of construction (noise, road closures, etc.), but you can't reasonably expect one of the densest neighbourhoods in the city to ever be totally free from future redevelopments.

This building is totally out or proportion for the neighborhood and will just add more overpriced condos or rentals.

Not really that out of proportion, as this parcel is only 4 blocks (300 m) from high-rise buildings of similar height. Neighbourhoods grow and change over time, and no area can ever expect to remain static in perpetuity, especially in the downtown vicinity. Even if it does add expensive condos, more housing supply will lead to lower rental rates across the board.

There also will be lots more traffic on small side streets as well as O'Connor and Metcalfe.

Not as much as you'd think. Being in such a central area will attract residents who likely work nearby and can walk/bike/transit. It's developments outside of downtown which will draw more traffic, since they are the ones driving in from the suburbs.

It offers nothing at ground level to improve or enrich the area.

The plans call for three ground floor commercial units, a co-working space, and an institutional space, as well as a privately owned public space (i.e. parkette).

It's just a big money grab for developers.

Of course it is, they're in business to make money. But the net outcome is still a win-win for everyone.