I could certainly see a short EF-S prime as a normal lens for APS-C. As for the 50/1.8 II update, that's one of Canon three top-selling lenses. Check out the 'updates' to the other two of the top three - the EF-S 18-55mm f/3.5-5.6 IS II and the EF-S 55-250mm f/4-5.6 IS II. No optical changes, just marginally cheaper production costs (even a small savings means big profit for the number of units sold).
Earlier this year, Canon hit a couple of sales milestones - 50 million EOS bodies and 70 million EF lenses (which includes EF-S). What does that mean? An average of 1.4 lenses per camera. Far and away, the most popular current lenses in addition to the 18-55 kit lens, are the EF-S 55-250 and the 50/1.8 II. To me, that suggests they probably sell relatively few non-L EF primes (50/1.8 notwithstanding). The 35/2 doesn't seem terribly popular, despite being 'normal' on APS-C. Since it's build and performance are similar to the 50/1.8 II, the far lower sales of the 35/2 are likely due to its higher price tag (cheap compared to most lenses, but still 3x the cost of the 50/1.8 II).
So, personally I think that if Canon does release an EF-S 28/30/35mm lens, it won't be the f/1.4 USM lens people who frequent this forum would probably prefer, but would likely cost well north of $400, perhaps $500-600. Instead, I think they'd telease an f/1.8 non-USM lens costing a bit over $200.