Edit This is also not groundbreaking or even new. The PR team is trying to spin the shitty telecommuting change of policy with an improved maternity/paternity leave. Not that an improvement is a bad thing itself.
I do hope you realize that building software takes time, particularly across a large co. like Yahoo. The policy changes are immediate effects which help formulate the company culture; the long term results are the products that will show up in the coming months and years.
Everyone I talked to legitimately thought that Marissa is bringing some much needed change to the company as far as I could tell, and I spoke to mostly software engineers, not PR people. Obviously opinions probably vary across the company and it's fairly large though.
The one "negative" thing she's done since coming on board is cut remote working, and I'm not convinced that was really so bad. Yahoo needed fix some internal stuff about the culture, and it would be hard to do that when your talented people are spread out all over the place. I agree that the management fluff needs a serious trimming there, so hopefully by bringing all the engineering talent in house, and theoretically trimming management, they can adjust the culture to be more engineering focused, which is what everyone wants.