It's unfortunate to hear about J&B, since downtown desperately needs more grocery locations, and can be a bit of a food desert. I'm guessing the place that's supposed to open in the ground floor of that Madison-King-Cameron-Charles block development will help since it'll have more floor area than basically any retail downtown, but that's also right next to New City and the market, and south of them -- pretty saturated. I'm guessing people in midtown (as I'm assuming you are) mostly go to Central Fresh. One of the things I feel Kitchener needs in order to have a strong urban residential lifestyle is more mid-sized neighbourhood grocery stores and to get away from the Weston's/Loblaws monolithic chain dominance, but that's a tough prospect when a lot of people attracted to areas like downtown probably eat out more often than not, and aren't cooking for a family. That said these things do reinforce each other, and it would be great to see a lot of the younger people moving into downtown stick around and help anchor a variety of businesses and not just restaurants.
This in a nutshell, in theory the ION could have taken King Street for its whole length and ignored the freight corridors, but this would have been punishingly slow and delivered no real service advantages over doing BRT with articulated buses. A lot of the wonky portions are due to getting on and off of the freight corridors, such as by Mill or Northfield. That said I am sympathetic to the critics of the one-way stations and loops, as I think TriTAG pointed out years ago that just biting the bullet and having two-way traffic on routes like Borden might have been better even if it closed the street permanently. If we're going to talk NIMBYism and especially about Stage 2 we should consider why the ION Stage 2 route avoids the CP corridor so pathologically, but happily runs next to the CN corridor and along the street -- the freight operators can be the biggest NIMBYs around.
If you look at the proposed plans a lot of areas are shaded in pink as being marked for future redevelopment, and I imagine a finalized Stage 2 route will see a similar land rush as what happened with Stage 1. Cambridge desperately needs transit-oriented development and I imagine if Stage 2 does end up with its 2028 date, by that point we will already see some higher density along the future corridor.