E6 Campaign help plz?

So, I'm planning out an E6 campaign for Pathfinder, and I'm trying to come up with the proper rules to do it... For those of you who don't know, an E6 campaign means that the levels stop at 6. All further progression is provided by feats, bought at 5000 XP a pop. All class features are then turned into feats, or feat chains, to allow a little bit of progressive multiclassing and leveling, but you're pretty much stuck with 3rd level spells and a +6/+1 BAB. I love the idea with this, but the shift in low power play has got me thinking about how the rules should reflect this change...

One thing I KNOW I want to implement is a simple rule. All 0 Level Spells and Powers now have a casting time of a Swift Action. Since they're unlimited, you can cast a spell every turn, and still do another action... I can't see anything but improvement with this, as low level casters can now do things past their 3 spell limit, but since one can be blind to their own creations I wanted to ask you what you thought of this house rule.

I'm also implementing the Death Flag and Conviction rules...

What houserules would you implement in a determined low level game?