The blank space at the top is absolutely reserved for toast notifications. It doesn't matter if you like it. Unless it changes in 8.1 or later, it's there to stay. I've given it a passing thought once or twice during my three years on windows phone, but of all annoyances, that reserved space is absolutely inconsequential. Most people will put their live tiles that matter at the top. E.g., phone, messaging, email, calendar, weather, me, etc. If the bottom row being partially obscured is really bothering you, consider exploring your creative side! If it is being cut off by half, why don't you pin a row of small tiles??? Problem solved.