Seems like a bunch of really welcome improvements. Wish I hadn't known about them though, as I probably won't be able to use them in our production environment for the next 2 years or so.
EDIT: meant PHP versions, not plugins.
You just need to put your foot down. 5.2 is absolutely too much, I would never develop for it. Just tell them to stop being so damn cheap and upgrade to a decent hosting company. AWS is free for a year for new clients, there's no reason for them not to switch to something decent.