Totally opinion, because I'm not a pre-med advisor and don't really know anything more than you do, but I would fill our your AMCAS application. Take the time to do it right, with multiple drafts of your personal statement and all that good stuff. Get your LORs brewing. Then wait for your MCAT scores. They will only delay your app by two to three weeks, which isn't bad. If they're better than your old ones, I'd apply this year, because like you say, you've improved your app. Your grades are higher, your MCATs are higher/newer, and you have more volunteer.
YMMV, good luck!