These are good points, but I don't think it's possible to
not see Yahoo as a behemoth. It's a big company, with lots of executives and fiefdoms. Just because there's a new CEO doesn't mean the kind of change that needs to happen will happen (and conversely, it's wrong to lay all the blame at Meyer's feet if things don't turn out well).
Case in point, look at how badly JCPenney fared after Apple retail exec, Ron Johnson, became CEO for just 17 months:
http://www.nytimes.com/2013/04/09/business/ron-johnson-out-a...
The fact that Yahoo can lay down $1.1 billion in cash is a show of how big the company is. That is both an asset and a liability, when it comes to the existing corporate power struggle.
edit: I'll give an example of which I'm familiar with, as a user: Flickr. I joined Flickr after Yahoo acquired it and have been a happy, paying user for nearly 4 years. However, I'd be at a loss to count all the new drastic feature additions that have come in all that time:
1. A new mobile app (which I don't use)
2. a nicer horizontal-masonry-like gallery layout...which, flabbergastingly, only applies to some collections of photos and not others
3. HTML5 uploader
And yet still, I count myself as a happy Flickr user, which means that prior to Yahoo's acquisition, Flickr was a great service to begin with. From what I can tell, as a data-minded person, Yahoo has done very little with all the interesting data that comes in these voluntarily organized and submitted photos. I don't get much help with auto-tagging or auto-grouping of collections. The Flickr logged-in homepage is nothing but a short list of the last few people who "favorited" a photo...there's been almost nothing done in four years to get me to engage more with the Flickr network.
And Flickr's domain covers items of a very discrete nature...easier to do interesting analysis and data-operations on than I feel one could do with Tumblr.
So while Flickr's relative stagnation is not Meyer's fault...the fact that we can say, "Well, it's not her fault that Flickr is meh five years in a row" goes to show you how massive a company Yahoo is and how hard it is for everything to move/change even when a new CEO comes in.