If you read the details, rather than just listening to the media, you'd be aware that 501 AM peak is planned to stay the same or increase with the new streetcars.
If you look at Steve Munro's article last year
http://stevemunro.ca/?p=6923 - particularly his chart on deployment -
http://stevemunro.ca/wp-content/uploads/2012/11/StreetcarFleetPlan201210.pdf you'd see the then current 31 ALRV vehicles in AM peak would be replaced by 33 new streetcars. (interestingly though, TTC is adding 5 CLRV trippers to this service on April 1 though - though the frequency of every 5.2 minutes isn't scheduled to change).
Off-peak loading standards are based on the number of seats per vehicle. The last page of the
current service summary shows that the number of seats only increases from 61 to 70. That shouldn't cause a huge change in frequency ... hopefully the growing off-peak demand for TTC service in recent years will offset the minor change in capacity.