I've noticed similar issues with the G3's inbuilt keyboard, which I've just got myself. Missing the Swype keyboard & it's features, & finding that Samsung's own is not quite up to par, I looked around for another.
Swiftkey seems to be very popular & from the demo I tried, it is VERY customisable. However, the current version (3) doesn't support continuous text entry, i.e. like Swype. They do have their own version in the works now, called Swiftkey Flow, but it's still in beta & hasn't been released for general testing yet. To sign up for possible beta access, you can use the following link:
Swiftkey Flow
Regarding the voice-to-text option, you should be able to enable this on the default keyboard, by following the below instructions:
> Enter the G3's text settings menu, by opening the text entry screen in a message & pressing the cog icon.
> Towards the bottom of the screen, just underneath the "Handwriting" toggle, you should see an option called "Voice input"; ensure that is checked.
(Now this is where a lot of people still seem to be stuck!)
> Back in your message text entry screen, bring up the keyboard & long-press the settings gear icon. A number of other icons should appear, including a microphone; select this.
> Now, back out to the keyboard again & the gear icon should be replaced with a mic icon, for quick & easy voice entry.
Hope this works for you. Not the easiest option to figure out, that's for sure.
Avi